1 : Internal conversion is where
a.the spin of an excited electron reverses, changing the state of the molecule (from singlet state to triplet state or vice versa)
b.A molecule converts its excess energy to light, and emits a photon
c.A molecule converts excess electronic energy to vibrational energy
d.none of the above
Answer : c

2 : Why phosphorescence measurements are usually made at a low temperature?
a.To prevent thermal degradation of the phosphorescent species
b.To promote phosphorescence by slowing the rate of radiationless transfer processes
c.To increase the efficiency of the detector
d.To decease the efficiency of detector
Answer : b

3 : Fluorescence occurs when
a.a molecule returns to the electronic ground state from an excited triplet state by losing it’s excess energy as a photon
b.a molecule returns to the electronic ground state from an excited singlet state by losing it’s excess energy as a photon
c.a molecule lowers its vibrational energy by losing it’s excess energy as a photon
d.none of the above
Answer : b

4 : What is the relationship between wavelength and wave number?
a.Wavenumber = 1 / wavelength in centimeters
b.Wavenumber – wavelength in nanometers = 1
c.Wavelength in nanometers x wavenumber = 1
d.None of the above
Answer : a

5 : In the intersystem crossing
a.the spin of an excited electron reverses, changing the state of the molecule (from singlet state to triplet state or vice versa)
b.a molecule converts its excess energy to light, and emits a photon
c.a molecule converts excess electronic energy to vibrational energy
d.all of the above
Answer : a

6 : Why must the radiation source for fluorescence spectrometry be more powerful than for absorption spectroscopy?
a.Because the magnitude of the output signal is proportional to the power of the incident radiation
b.Because the sample won’t fluoresce if the incident radiation is of low power
c.To allow for scattering by the sample
d.None of the above
Answer : a

7 : Why do fluorescence spectrometers often use double-beam optics?
a.So a reference solution can be used
b.To compensate for beam attenuation by the monochromator
c.To compensate for power fluctuations in the radiation source
d.All of the above
Answer : c

8 : For a molecule to absorb IR, why must the molecule’s vibrations cause fluctuations in the dipole moment of the molecule?
a.Because a change in dipole moment lowers the energy required for electronic transitions
b.Because for absorption to occur, the radiation must interact with the electric field caused by changing dipole moment
c.Because fluctuations in the dipole moment allow the molecule to deform by bending and stretching
d.All of the above
Answer : b

9. If the absorption of electromagnetic radiation by matter results in the emission of radiation of the same or longer wavelengths for a long or a short time, the phenomenon is termed as which of the following?
a) Luminescence
b) Fluorescence
c) Phosphorescence
d) Spontaneous emission
Answer: a
Explanation: If the absorption of electromagnetic radiation by matter results in the emission of radiation of the same or longer wavelengths for a short or a long time, the phenomenon is termed as luminescence. Usually, absorption of electromagnetic radiation results in the emission of radiation.

10. If the absorption of electromagnetic radiation by matter results in the emission of radiation of the same or longer wavelengths for a short time, the phenomenon is termed as which of the following?
a) Luminescence
b) Fluorescence
c) Phosphorescence
d) Spontaneous emission
Answer: b
Explanation: If the absorption of electromagnetic radiation by matter results in the emission of radiation of the same or longer wavelengths for a short time, the phenomenon is termed as fluorescence. Fluorescence emissions are characteristic of the particular element.

11. If the absorption of electromagnetic radiation by matter results in the emission of radiation of the same or longer wavelengths for a long time, the phenomenon is termed as which of the following?
a) Luminescence
b) Fluorescence
c) Phosphorescence
d) Spontaneous emission
Answer: c
Explanation: If the absorption of electromagnetic radiation by matter results in the emission of radiation of the same or longer wavelengths for a long time, the phenomenon is termed as phosphorescence. Phosphorescence is a type of luminescence.

12. Prompt emission of X-ray by an atom ionised by a higher energy X-ray is a type of which of the following phenomena?
a) Luminescence
b) Fluorescence
c) Phosphorescence
d) Spontaneous emission
Answer: b
Explanation: Prompt emission of X-ray by an atom ionised by a higher energy X-ray is a type of fluorescence. Fluorescence emissions are characteristic of the particular element.

13. The measurement of intensity of fluorescent X-rays provide a simple and ____________ way of _____________ analysis.
a) Destructive, quantitative
b) Non-destructive, quantitative
c) Destructive, qualitative
d) Non-destructive, qualitative
Answer: b
Explanation: The measurement of an intensity of fluorescent X-rays provide a simple and non-destructive way of quantitative analysis.

14. The energy of the emitted X-rays depends upon the _________ of the atom and their intensity depends upon the __________
a) Atomic number, amount of sample
b) Mass number, amount of sample
c) Mass number, concentration of atoms
d) Atomic number, concentration of atoms
Answer: d
Explanation: The energy of the emitted X-rays depends upon the atomic number of the atom and their intensity depends upon the concentration of atoms in the sample. X-ray fluorescence spectroscopy is based on this principle.

15. Which of the following is Mosely’s equation if ‘C’ is the speed of light, ‘a’ is proportionality constant, ‘σ’ is a constant which depends on electronic transition series, ‘Z’ is the atomic number and ‘λ’ is the wavelength?
a) Cλ= a(Z-σ)2
b) C/λ= a(Z-σ)2
c) C(Z-σ)2= aλ
d) C(Z-σ)2= a/λ

16. The problem of spectral interference is not severe in X-ray spectroscopy.
a) True
b) False
Answer: a
Explanation: The problem of spectral interference is not severe in X-ray spectroscopy. This is due to the relative simplicity of the X-ray spectra.

17. In X-ray fluorescence spectrometer, the relationship between the excitation intensity and the intensity of fluorescence does not depend on which of the following?
a) Spectrum of the incident radiation
b) Angle of radiance
c) Molecular weight
d) Incident angle
Answer: d
Explanation: In X-ray fluorescence spectrometer, the relationship between the excitation intensity and the intensity of fluorescence does not depend on the incident angle. It depends on the absorption of path length.

18. Fluorescent X-ray spectrometers would require only moderate-intensity X-ray tubes.
a) True
b) False
Answer: b
Explanation: Fluorescent X-ray spectrometers would require high-intensity X-ray tubes. They also require sensitive detectors and suitable X-ray optics.

19. The fact that the fluorescence wavelength is often much longer than the irradiation wavelength (Stokes shift) is a consequence of which phenomenon?
a) low extinction coefficients (Lambert-Beer law)
b) vertical transitions (Kasha’s rule)
c) high ISC rates (El Sayed rule)
d) the Franck–Condon principle
Answer: d
Explanation: The reason why Stokes shifts occur is the Franck–Condon principle, which states that a change in the electronic state of some molecule caused by the absorption of a photon occurs so rapidly that the motion of the nuclear coordinates during the transition can be neglected. After the electronic transition is complete, the molecule’s nuclear coordinates then relax into a lower-energy configuration in response to the change in the electronic wave function.

20. Which of the following is an incorrect statement?
a) First step in photochemistry is excited state (photoexcitation)
b) Photochemical reactions are caused by absorption of ultraviolet only
c) When a molecule or atom in the ground state (S0) absorbs light, one electron is excited to a higher orbital level
d) It is possible for the excited state S1 to undergo spin inversion
Answer: b
Explanation: Photochemical reactions are caused by absorption of ultraviolet, (wavelength from 100 to 400 nm), visible light (400 – 750 nm) or infrared radiation (750 – 2500 nm).

21. Which regions of the light radiations of the visible ultraviolet lying between – wavelength are chiefly concerned in bringing about photochemical reactions?
a) 1000 Å and 2000 Å
b) 1500 Å and 1000 Å
c) 8000 Å and 2000 Å
d) 19000 Å and 12,000 Å
Answer: c
Explanation: The region of interest for photochemistry is between 8000 Å and 2000 Å of visible and ultraviolet (UV), are only a small part of the full electromagnetic spectrum. Longer wavelengths, e.g., far infrared, tend to cause the vibrational excitation of molecules, which results in heating. Shorter wavelength X-rays cause ionization.

22. Which of the following instruments is used to measure the energy of the monochromatic radiation most accurately?
a) Photoelectric cell
b) Thermopile
c) The potential detector
d) The chemical actinometer
Answer: b
Explanation: A thermopile is an electronic device that converts thermal energy into electrical energy. It is composed of several thermocouples connected usually in series or, less commonly, in parallel.

23. The molar extinction coefficient of B (MW = 180) is 4 x 103 L mol-1 cm-1. One-liter solution of C which contains 0.1358 g pharmaceutical preparation of B, shows an absorbance of 0.411 in a 1 cm quartz cell. What is the percentage (w/w) of B in the pharmaceutical preparation?
a) 10.20
b) 13.60
c) 20.40
d) 29.12
Answer: b
Explanation:

24. What are the appropriate reasons for the deviation from the Beer’s law among the following?
(A) Monochromaticity of light
(B) Very high concentration of analyte
(C) Association of analyte
(D) Dissociation of analyte
a) A, B and D
b) B, C and D
c) A, C and D
d) A, B and C
Answer: b
Explanation: Reasons for derivation from Beer’s law are very high concentration of analyte, Association or Dissociation of analyte and Refractive index → Polychromatic light. Monochromaticity of light don’t have any effect on Beer’s law.

25. Which of the following will result in deviation from Beer’s law?
(A) Change in a refractive index of medium
(B) Dissociation of analyte on dilution
(C) Polychromatic light
(D) Path length of cuvette
a) A, B and C
b) B, C and D
c) A, C and D
d) A, B and D
Answer: a
Explanation: Change in a refractive index of medium, Dissociation of analyte on dilution and Polychromatic light (reflective index) will result in deviation from Beer’s law.

26. The quantum efficiency of a photochemical reaction is defined as _______
a) ratio of molecules decomposed in a given time to the number of quanta absorbed in the same time
b) number of 11101ecules decomposed in a given time
c) number or quanta absorbed percent time
d) ratio of’ molecules decomposed in a given time to the number of quanta emitted in the same time
Answer: a
Explanation: According to the definition ratio of molecules decomposed in a given time to the number of quanta absorbed at the same time is the correct option.

27. Which of the following are the reactions in which molecules absorbing light do not themselves react but induce other molecules to react?
a) Free radical reactions
b) Chain reactions
c) Reversible reactions
d) Photosensitized reactions
Answer: d
Explanation: Photosensitized reactions is the reactions in which molecules absorbing light do not themselves react but induce other molecules to react.

1. The charge required for the reduction of 1 mol of MnO₄^– to MnO₂ is
(a) 1 F
(b) 3 F
(c) 5 F
(d) 6 F
Answer: b

2. The cell reaction of the galvanic cell.

Answer: d

3. Which of the following reaction is used to make fuel cell?

Answer: c

4. If limiting molar conductivity of Ca²⁺ and Cl^– are 119.0 and 76.3 S cm² mol^-1, then the value of limiting molar conductivity of CaCl2 will be
(a) 195.3 S cm² mol^-1
(b) 271.6 S cm² mol^-1
(c) 43.3 S cm² mol^-1
(d) 314.3 S cm² mol^-1.
Answer: b

5. NH4NC>3 is used in salt bridge because
(a) it forms a jelly like material with agar-agar.
(b) it is a weak electrolyte.
(c) it is a good conductor of electricity.
(d) the transport number of NH₄⁺ and NO₃^– ions are almost equal.
Answer: d

6.

Answer: b

7. The reaction, 3ClO^– (aq) → ClO₃ (aq) + 2Cl^– (aq) is an example of
(a) Oxidation reaction
(b) Reduction reaction
(c) Disproportionation reaction
(d) Decomposition reaction
Answer: c

8. The emf of the cell:
Ni / Ni²⁺ (1.0 M) // Au³⁺ (1.0 M) / Au (E° = -0.25 V for Ni²⁺/Ni; E° = 1.5 V for Au³⁺/Au) is
(a) 1.25 V
(b) -1.25 V
(c) 1.75 V
(d) 2.0 V
Answer: c

9. The standard emf of a galvanic cell involving cell reaction with n = 2 is formed to be 0.295 V at 25° C. The equilibrium constant of the reaction would be
(a) 1.0 × 10¹⁰
(b) 2.0 × 10¹¹
(c) 4.0 × 10¹²
(d) 1.0 × 10²
[Given F = 96500 (mol^-1); R = 8.314 JK^-1 mol^-1]
Answer: a

10. If E°_Fe²⁺/Fe = -0.441 V and E°_{Fe²⁺/Fe²⁺} = 0.771 V, the standard EMF of the reaction,
Fe + 2Fe³⁺ → 3Fe²⁺ will be
(a) 1.212 V
(b) 0.111 V
(C) 0.330 V
(d) 1.653 V
Answer: a

11. The aqueous solution of which of the following compounds is the best conductor of electric current?
a.Acetic acid,
b.Hydrochloric acid
c.Ammonia
d.Fructose
Answer: (b)

12. An increase in the conductivity equivalent of a solid electrolyte with dilution is primarily due to
a.increased ionic mobility of ions
b.100 percent electrolyte ionisation with natural dilution
c.increase in both ion numbers and ionic mobility
d.A rise in ion counts
Answer: (a)

13. The equivalent conductance of Ba2+ and Cl– are respectively 127 and 76 ohm-1 cm-1 eq-1 at infinite dilution. The equivalent conductance of BaCl2 at infinite dilution will be
a.139.5
b.203
c.279
d.101.5
Answer: (a)

14. When heating one end of a metal plate, the other end gets hot because of
a.the resistance of the metal
b.mobility of atoms in the metal
c.energised electrons moving to the other end
d.minor perturbation in the energy of atoms.
Answer: (c)

15. The weight of silver displaced by a quantity of electricity which displaces 5600ml of O2 at STP will be
a.5.4g
b.10.8g
c.54.9g
d.108.0g
Answer: (d)

16. Once a current of 1.0 ampere was passed through one litre of CuCl2 solution for 16 min and 5 sec, all of the solution’s copper was deposited at the cathode. The strength of solution CuCl2 was (Molar mass of Cu = 63.5; Faraday constant = 96,500 C/mol)
0.01N
0.01M
0.02M
0.2N
Answer: (a)

17. On electrolysis of dilute sulphuric acid using platinum electrodes, the product obtained at the anode will be
a.hydrogen
b.oxygen
c.hydrogen sulphide
d.sulphur dioxide
Answer: (b)

18. A device that converts the energy of combustion of fields like hydrogen and methane directly into electrical energy is known as
a.Electrolytic cell
b.Dynamo
c.Ni-Cd cell
d.Fuel cell
Answer: (d)

19. Which reaction is not feasible?
a.2KO + Br2 → 2KBr + I2
b.2KBr + I2 → 2KI + Br2
c.2KBr + Cl2 → 2KCl + Br2
d.2H2O + 2F2 → 4HF + O2
Answer: (b)

20. Without losing its concentration ZnCl2 solution cannot be kept in contact with
a.Au
b.Al
c.Pb
d.Ag
Answer: (b)

1. The most common method of preventing corrosion is the selection of the proper metal or alloy for a particular corrosive service.
a) True
b) False
Answer: a
Explanation: There is no such single material that can be used in all environment conditions and all temperature ranges. So, it is important to select a proper metal or alloy for a particular corrosive service. It prevents or reduces the corrosion damage of the metallic structure.

2. Which of the following composition range is correct regarding stainless steel?
a) 11.5 to 30% chromium and 10 to 22% nickel
b) 11.5 to 30% chromium and 0 to 22% nickel
c) 0 to 30% chromium and 0 to 22% nickel
d) 0 to 30% chromium and 10 to 22% nickel
Answer: b
Explanation: Stainless steel is the generic name for a series of more than 30 different alloys with composition ranges from 11.5% to 30% chromium and 0 to 22% nickel and other alloying elements.

3. Which of the following types of corrosion in which stainless steels are more susceptible than ordinary steels?
a) Pitting corrosion
b) Stress-corrosion cracking
c) Intergranular corrosion
d) Stress-corrosion cracking, pitting and intergranular corrosion
Answer: d
Explanation: Stainless steels are more susceptible to localized corrosion such as intergranular corrosion, stress-cracking corrosion, and pitting corrosion than ordinary steels. Instability of oxide layer in severe corrosive conditions and sensitizing temperature are the reasons for the susceptibility of stainless steel.

4. Which of the following metal is the best material selection combination for the nitric acid environment?
a) Tin
b) Nickel and its alloys
c) Stainless steels
d) Steel
Answer: c
Explanation: Stainless steels are the best combination of metal for the nitric acid environment. Stainless steels readily form a passive oxide film in nitric acid. This minimizes or reduces the corrosion damage.

5. Which of the following metal is the best material selection combination for the caustic environment?
a) Titanium
b) Nickel and its alloys
c) Steels
d) Aluminum and its alloys
Answer: b
Explanation: Nickel and its alloys are the best combination of metal for the caustic environment. Metals such as titanium and high tensile strength steels are prone to caustic embrittlement.

6. Which of the following metal is the best material selection combination for distilled water?
a) Tin
b) Lead
c) Titanium
d) Nickel
Answer: a
Explanation: Tin is the best combination of metal for distilled water. Tin or tin coatings are almost always chosen as a container or piping material for very pure distilled water.

7. Which of the following metal is/are the correct combination for reducing or non-oxidizing environment?
a) Nickel and its alloys
b) Copper and its alloys
c) Stainless steels
d) Nickel, copper and its alloys
Answer: d
Explanation: Nickel, copper and its alloys are the correct combinations of metals for reducing or non-oxidizing environments. Whereas stainless steels and titanium alloys are stable in an oxidizing environment.

8. Which of the following material is used for handling hydrogen peroxide?
a) Commercially pure metals
b) Alloys
c) Both commercially pure metal and alloys
d) Neither commercially pure metals nor alloys
Answer: a
Explanation: Commercially pure metal such as aluminum (99.5 purity) is used for handling hydrogen peroxide. Alloys result in the decomposition of hydrogen peroxide due to the catalytic action of alloying elements.

9. Which of the following type of zirconium is used in an atomic-energy application?
a) Induction-melted zirconium
b) Arc-melted zirconium
c) Both arc-melted and induction-melted zirconium
d) Neither arc-melted nor induction melted zirconium
Answer: b
Explanation: Arc-melted zirconium is more corrosion resistant than induction-melted zirconium because of more impurities in the latter. Hence arc-melted zirconium is used in an atomic-energy application.

10. Which of the following is/are the different classes of non-metallics?
a) Ceramics and wood
b) Plastics and ceramics
c) Wood, ceramics, and plastic
d) Ceramics only
Answer: c
Explanation: The five general classes of non-metallics are:
Natural and synthetic rubber
Plastics
Ceramicsi
Carbon and graphite.
Wood.

11. Which of the following type of materials possess excellent corrosion and high-temperature resistance?
a) Metals
b) Plastics
c) Ceramics
d) Both ceramics and metals
Answer: c
Explanation: Ceramics are the class of materials that possess excellent corrosion and high-temperature resistance. But brittleness or less tensile strength is the primary limitation of ceramics.

12. Boiling seawater is less corrosive than that of hot seawater.
a) True
b) False
Answer: a
Explanation: Boiling seawater is less corrosive than that of hot seawater. Because the solubility of oxygen in seawater decreases with an increase in temperature. Reduction of oxygen results in severe metallic dissolution in many oxygenated corrosive solutions.

13. Which of the following belongs to the alteration of the environment to minimize corrosion?
a) Decreasing velocity
b) Removing oxygen and oxidizers
c) Changing concentration
d) Decreasing velocity, removing oxygen and oxidizers and changing the concentration
Answer: d
Explanation: Alteration of the environment is one of the measures to minimize corrosion. Alteration of the environment includes
Changing mediums
Lowering temperature
Decreasing velocity
Removing oxidizers
Changing concentrations.

14. Which of the following is/are the functions of magic devices or water-conditioning gadgets?
a) Prevent scaling
b) Destroy bacteria
c) Reduce water hardness
d) Prevent scaling, destroy bacteria and reduce water hardness
Answer: d
Explanation: Magic device or water-conditioning gadgets are the devices to control water corrosion. Purpose of these gadgets are
Prevent scaling
Destroy bacteria
Reduce water hardness
Reduces corrosion.

15. Which of the following metal combination is/are selected as per given requirement in the figure?

a) Gold – Iron
b) Steel – Stainless
c) Brass – Copper
d) Silver – Zinc
Answer: b
Explanation: The given figure indicates the galvanic metal combination. Hence metal combination should be as close as possible in the galvanic series to minimize the galvanic effect. Hence good metal combination is brass and copper.

16. Cathodic protection is achieved by supplying electrons to the metal structure to be protected.
a) True
b) False
Answer: a
Explanation: Cathodic protection is achieved by supplying electrons to the metal structure to be protected. It can be done by using impressed current in the range of microamperes per unit area of the metallic structure.

17. Which of the following cases in which the metal structure is protected?
a) Current passes from metal to electrolyte
b) Current enters it from the electrolyte
c) Electrical contact with dissimilar metals
d) Connecting the positive terminal of the power supply
Answer: b
Explanation: Metallic structure can be protected when the impressed current is arranged to enter it from the electrolyte. Whereas current passes from metal to electrolyte, electrical contact with dissimilar metals, and connecting the positive terminal of the power supply results in accelerated corrosion.

18. Which of the following is/are the types of cathodic protection?
a) External impressed current supply
b) Sacrificial anode
c) External impressed current supply and sacrificial anode
d) Neither external impressed current supply nor sacrificial anode
Answer: c
Explanation: Cathodic protection is achieved by supplying electrons to the metal structure to be protected. Types of cathodic protection are i. External impressed current supply ii. Sacrificial anode.

19. Which of the following terminal of the power supply should be connected to the metal to be protected?
a) Negative terminal
b) Positive terminal
c) Both positive and negative terminals
d) Either positive or negative terminal
Answer: a
Explanation: As the conventional electrical theory states that current flows from () to (-), the structure is protected if the negative terminal of the power supply is connected metallic structure.

20. Which of the following method is depicted in the given figure?

a) Anodic protection
b) Impressed current supply
c) Sacrificial anode
d) Anodic and cathodic protection
Answer: b
Explanation: Impressed current supply is a method of cathodic protection that is achieved by supplying electrons to the metal structure to be protected. The given figure depicted is impressed current supply method of an underground tank.

21. Which of the following material is/are used as an impressed-currents anode?
a) Graphite
b) Platinized titanium
c) Silicon-iron
d) Graphite, platinized titanium, and silicon-iron
Answer: d
Explanation: Materials that can be used as an impressed-currents anode are:
Graphite
Platinized titanium
Silicon-iron
Steel.

22. Which of the following materials is/are used as backfill around the anode in impressed currents?
a) Coke breeze
b) Gypsum
c) Bentonite
d) Coke breeze, gypsum, and bentonite
Answer: d
Explanation: Coke breeze, gypsum, and bentonite are the materials that are used as backfill material around the anode. These materials improve the electric contact between the anode and surrounding soil.

23. Which of the following protection method is depicted in the given figure?

a) Impressed-current supply method
b) Anodic protection
c) Sacrificial anode
d) Anodic protection and sacrificial anode
Answer: c
Explanation: Sacrificial anode method is one the type of cathodic protection in which a metal (anode) corrodes preferentially than the metallic structure. Sacrificial anodes are inexpensive and easily available in nature.

24. Which of the metallic structure will require more impressed current density for cathodic protection?
a) Water heaters in hot freshwater
b) Underground pipelines
c) The storage tank of H2SO4
d) Reinforcement rods
Answer: c
Explanation: Impressed method current is an external supply of power to provide electrons to metallic structure that needs to be protected. The storage tank of H2SO4 requires the highest current density per sq. feet due to the high corrosiveness of acid.

25. Which of the corrosion prevention method is used for reducing the maintenance cost of highway and bridges?
a) Sacrificial anode
b) Impressed current supply
c) Anodic protection
d) Use of inhibitors
Answer: b
Explanation: Impressed current supply is used as the corrosion prevention for reducing maintenance costs of big metallic structures such as highways and bridges. It also used to reduce the corrosion of reinforced steel.

26. Which of the following is depicted in the given figure?

a) Anodic protection
b) Impressed current supply
c) Stray current effect
d) Sacrificial anode
Answer: c
Explanation: The given figure depicts the stray current effect that usually caused to the dense pipelines in the vicinity of a tank or pipeline protected by the impressed current system.

27. Anodic protection is based on the formation of a protective film on metals by external applied anodic currents.
a) True
b) False
Answer: a
Explanation: Anodic protection is one of the corrosion prevention methods that is based on the formation of a protective film on metals by external applied anodic currents.

28. Which of the following metals can be protected using anodic protection?
a) Nickel and iron
b) Nickel, iron, and titanium
c) Titanium only
d) Nickel, iron, titanium, and magnesium
Answer: b
Explanation: Anodic protection can be used only for active-passive transition metals as it provides external current for the formation of a passive oxide layer. Active-passive transition metals include nickel, iron, aluminum, titanium, and its alloys.

29. A potentiostat is an electronic device that maintains a metal at a constant potential to a reference electrode.
a) True
b) False
Answer: a
Explanation: A potentiostat is an electronic device that maintains a metal at a constant potential to a reference electrode. It is required to protect a metal anodically by a passivating metal surface.

30. Which of the following corrosion prevention method is depicted in the given figure?

a) Sacrificial anode
b) Impressed current supply method
c) Use of inhibitors
d) Anodic protection
Answer: d
Explanation: Anodic protection of a storage tank is depicted in the given figure. A potentiostat is used to maintain the constant potential for a metallic structure against the reference electrode that results in passivity.

31. Which of the following auxiliary cathode is used for anodic protection?
a) Graphite
b) Platinized titanium
c) Platinum-clad electrode
d) Aluminum electrode
Answer: c
Explanation: It is necessary to have an inert auxiliary cathode such as a platinum-clad electrode as the anode provides external electric current to passivates the metallic structure.

32. Which of the following reference electrode is used in anodic protection?
a) Standard hydrogen electrode
b) Copper/copper sulfate reference electrode
c) Standard hydrogen electrode and calomel electrode
d) Calomel electrode
Answer: d
Explanation: The Calomel electrode is used to measure the potential maintained during the operation. It is connected to the third terminal of potentiostat whereas metal and auxiliary cathode are connected to first and second terminals respectively.

33. Which of the following is/are the advantages of anodic protection than cathodic protection?
a) Availability in extremely corrosive conditions
b) Low current requirement
c) Availability in extremely corrosive conditions and low current requirement
d) Very low installation cost
Answer: c
Explanation: Advantages of anodic protection than cathodic protection is:
i. Availability in extremely corrosive conditions
ii. Low current requirement.

34. Which of the following is/are the unique advantages of anodic protection?
a) To monitor instantaneous corrosion rate
b) Operating conditions can be established in the lab
c) It is applicable for all type of metals
d) To monitor instantaneous corrosion rate and operating conditions can be established in the lab
Answer: d
Explanation: Unique advantages of anodic protection are:
i. To monitor the instantaneous corrosion rate of a metal
ii. Operating condition of anodic protection can be precisely established in the lab.

35. A thin coating of metallic and inorganic materials can provide a satisfactory barrier between the metal and its environment.
a) True
b) False
Answer: a
Explanation: A thin coating of metallic, inorganic, and organic material can provide a satisfactory barrier between the metal and its environment. Because it minimizes the exposure of native metal to the corrosive environment.

36. Which of the following is/are the purposes of coatings?
a) To acts as a sacrificial metal
b) To act as an effective barrier
c) Either to act as sacrificial metal or to act as an effective barrier
d) Neither to act as sacrificial metal nor to act as an effective barrier
Answer: c
Explanation: Coatings are the relatively thin material portion on the surfaces of native metal to avoid direct exposure to the corrosive environment. The purpose of coatings is either to act as sacrificial metal or to act as an effective barrier.

37. Which of the following is/are the methods to apply metallic coatings?
a) Electrode position
b) Flame spraying
c) Cladding
d) Electrode position, flame spraying, and cladding
Answer: d
Explanation: Methods to apply metallic coatings are:
i. Electrode position
ii. Flame spraying
iii. Cladding
iv. Hot dipping
v. Vapor deposition.

38. What is the reason for the localized attack on the base metal due to the porosity of coatings?
a) Crevice formation
b) Galvanic effect
c) Initiation of pits
d) Crevice formation and galvanic effect
Answer: b
Explanation: The localized attack on the base metal due to the porosity of coatings is dueto two-metal corrosion or galvanic effect. Because metal coating and base metal are electrically connected in a corrosive environment.

39. Which of the following is/are the examples for metal-coated articles?
a) Silverware
b) Galvanized steel
c) Tin cans
d) Silverware, galvanized steel, and tin cans
Answer: d
Explanation: Sacrificial metals such as zinc, tin, and precious metals such as silver, gold, platinum is used as metallic coatings for various applications. Silverware, galvanized steel, and tin cans are examples of metallic coatings.

40. What is meant by electrodeposition?
a) Immersing native metal in a solution of the metal to be plated
b) Hot rolling of two metals together to get a composite sheet
c) A wire or powder through melting flame is blown onto the surface to be protected
d) Coating metal is vaporized electrically to deposit on the metals to be coated
Answer: a
Explanation: Electrode position is an immersion of native metal in a solution of the metal to be plated with direct current passing through them. It is also called electroplating.

41. Which of the following is/are the factors of electroplating that effects efficiency?
a) Temperature and composition of the bath
b) Composition of bath and time
c) Temperature, the composition of the bath, time and current density
d) Current density and composition of the bath
Answer: c
Explanation: Factors that affect the efficiency of electroplating are:
i. Temperature
ii. Current density
iii. Time
iv. Composition of bath.

42. What is the general purpose of each coating in a three-layered coating of an automobile bumper?
a) Inner coating – adhesion, intermediate coating – corrosion protection and top layer – appearance
b) Inner coating – corrosion protection, intermediate coating – adhesion and top layer – appearance
c) All layers for corrosion resistance
d) All layers for appearance
Answer: a
Explanation: In general, multiple layered metallic structures consist of inner coating for adhesion such as copper, intermediate coating for corrosion resistance such as nickel and top coatings for appearance such as chromium.

43. What is meant flame spraying metallic coating?
a) Hot rolling of two metals together to get a composite sheet
b) A wire or powder through melting flame is blown onto the surface to be protected
c) Coating metal is vaporized electrically to deposit on the metals to be coated
d) Immersing native metal in a solution of the metal to be plated
Answer: b
Explanation: Flame spraying metallic coating is a method of metal coating in which a wire or powder through the melting flame is blown onto the surface to be protected. Oxygen, acetylene, and propane are used for melting flame.

44. Which of the following is/are the application of flame spraying?
a) Bridges
b) Refrigeration equipment
c) Ship hulls
d) Bridges, refrigeration equipment and ship hulls
Answer: d
Explanation: Application of flame spraying include vessels of all kinds, bridges, ship hulls, refrigeration equipment, and many fabricated steel products. Low melting point metals such as zinc, tin, and lead are used.

45. What is meant by chemical conversion regarding coatings of a metal?
a) Coating metal is vaporized electrically to deposit on the parts to be coated
b) Coatings produced by corroding the metal surface to form an adherent protective layer
c) Hot rolling of two metals together to produce composite sheet
d) A metal wire or powder through the melting flame is blown onto the surface to be protected
Answer: b
Explanation: Chemical conversion is one of the surface coating methods in that coatings are produced by corroding the metal surface to form an adherent protective layer.

46. Which of the following is/are the examples of chemical conversion?
a) Bonderizing
b) Parkerizing
c) Chromatizing
d) Bonderizing, parkerizing, and chromatizing
Answer: d
Explanation: Bonderizing, parkerizing, and chromatizing are examples of chemical conversion. Automobile bodies are best known for phosphatizing treatment. Anodized aluminum with a protective film Al2O3 is another example.

47. In general, coatings should not be used where the environment would rapidly attack the substrate material.
a) True
b) False
Answer: a
Explanation: In general, coatings should not be used where the environments would rapidly attack the substrate material because one defect or small area of exposed metal would result in rapid degradation.

48. Which of the following is/are the examples of organic coatings?
a) Paints
b) Varnishes
c) Lacquers
d) Paints, varnishes and lacquers
Answer: d
Explanation: Organic coatings are widely used to protect more metals on a tonnage basis than other corrosion combating processes. Organic coatings include paints, varnishes, and lacquers.

49. Which of the following is/are factors to consider for organic coatings?
a) Surface preparation only
b) Surface preparation and selection of primary coating
c) Surface preparation and selection of primary and top coatings
d) Selection of primary and top coatings
Answer: c
Explanation: Factors to consider for organic coatings are:
i. Surface preparation usually is done by sandblasting
ii. Selection of primary coatings for strong adhesive bonding
iii. Selection of top coating for appearance and corrosion resistance.

50. What is the purpose of surface preparation?
a) Surface roughening for mechanical bonding
b) Removal of dirt, rust and mill scale
c) Removal of welding flux and other impurities
d) Surface roughening for mechanical bonding, removal of dirt, rust, mill scale, welding flux, and other impurities
Answer: d
Explanation: Surface preparation is a crucial part of the stability of coatings. It roughens the surface to obtain mechanical bonding, removal of dirt, rust, mill scale, welding flux, and other impurities.

51. Which of the following is/are the methods for surface preparation for coating application?
a) Sandblasting and chipping
b) Wire brushing and flame cleaning
c) Sandblasting, chipping, wire brushing and flame cleaning
d) Sandblasting, chipping and flame cleaning
Answer: c
Explanation: Methods for surface preparation for coating application are:
i. Sandblasting
ii. Wire brushing
iii. Flame cleaning
iv. Chipping
v. Scarping.

52. Which of the following paints are widely used for corrosion applications?
a) Vinyl and epoxy paints
b) Asphalts and bituminous paints
c) Iron oxide and titanium oxide paints
d) Alkyds and red lead
Answer: a
Explanation: A variety of paints are available in the market for various corrosion applications. It includes asphalts, bituminous paints, red lead, iron oxide, titanium oxide, alkyds, vinyl, and epoxies. Among them, vinyl and epoxies are the class of paints that are widely used for corrosion applications.

53. Which of the following is/are the characteristics of primers or primary coatings?
a) It contains rust-inhibitive pigments only
b) Adequate wettability and short drying time
c) Short drying time, adequate wettability and it contains rust-inhibitive pigments
d) It contains rust-inhibitive pigments and short drying time
Answer: c
Explanation: Characteristics of primary coatings are:
i. It contains rust-inhibitive pigments
ii. Adequate wettability
iii. Short drying time.

54. Which of the following is/are the advantages of coal-tar coatings?
a) Excellent corrosion resistance to fresh and seawater
b) Excellent corrosion resistant to fresh, seawater and soil immersion
c) High abrasive resistance
d) Stable coating
Answer: b
Explanation: Coal-tar coatings are excellent corrosion resistant to fresh, seawater, and soil immersion. Whereas its abrasive resistance and stability of coating are its limitations.

55. What is the important basis for the classification of corrosion?
a) Appearance of corroded metal
b) Nature of metal
c) Environmental conditions
d) Corrosion rate
Answer: a
Explanation: The basis for the classification of corrosion is the appearance of corroded metal. Each form can be identified by visual observation as it has a unique form of appearance.

56. Which of the following is/are types of corrosion?
a) Erosion corrosion
b) Galvanic corrosion
c) Pitting corrosion
d) Erosion, galvanic and pitting corrosion
Answer: d
Explanation:
Types of corrosion: i. Uniform corrosion
ii. Galvanic corrosion
iii. Crevice corrosion
iv. Pitting corrosion
v. Intergranular corrosion
vi. Selective leaching
vii. Erosion corrosion
viii. Stress corrosion

57. Which of the following type of corrosion is depicted in the given figure?

a) Pitting corrosion
b) Uniform corrosion
c) Erosion corrosion
d) Selective leaching
Answer: b
Explanation: Uniform corrosion is an electrochemical corrosion in which metal undergoes uniform depth of deterioration over its entire exposed surface. Example: Rusting of iron in atmospheric air.

58. Which of the following is an example of uniform corrosion?
a) Zinc dissolution in dilute H2SO4
b) Dezincification of brass in acids
c) Rusting of iron
d) Zinc dissolution in dilute H2SO4 and rusting of iron
Answer: d
Explanation: Uniform corrosion is characterized by an electrochemical reaction that proceeds uniformly over the entire exposed surface. Zinc dissolution in dilute H2SO4 and rusting of iron are examples of uniform corrosion. Dezincification of brass in acids is an example of selective leaching.

59. Tarnishing of silver is an example of which type of corrosion?
a) Crevice corrosion
b) Pitting corrosion
c) Uniform corrosion
d) Erosion corrosion
Answer: c
Explanation: Outermost layers of silver undergoes a chemical reaction with hydrogen sulfide results in tarnish. This is known as the tarnishing of silver. Metals like brass, copper, aluminum, silver, and magnesium undergoes tarnishing under various corrosive environments.

60. What is/are the preventions of uniform corrosion?
a) Proper material coatings
b) Inhibitors
c) Cathodic protection
d) Proper material coatings, inhibitors, and cathodic protection
Answer: d
Explanation: Uniform corrosion can be prevented by proper material coatings, inhibitors, and cathodic protection. Proper material coatings minimize the exposure area of metal. An inhibitor is a chemical substance that decreases the corrosion rate of metal by modifying the surface of anode or cathode.

61. Which of the following is/are the causes of catastrophic failures of corrosion?
a) Incomplete weld penetration
b) Extremely porous casting
c) Improper heat treatment
d) Incomplete weld penetration, extremely porous casting and improper heat treatment
Answer: d
Explanation: Corrosion is an electrochemical reaction that results in the degradation of a material. Corrosion failures are usually catastrophic in nature. And the causes are incomplete weld penetration, extremely porous casting, and improper heat treatment.

62. What is the standard electrode potential of Fe+2/Fe?
a) 0.0 V
b) +0.36
c) -0.44
d) -0.76
Answer: c
Explanation: Standard reduction potential of hydrogen ion, copper, iron, and zinc Is 0.0V, +0.36V, -0.44V and -0.76V respectively. These are measured against the standard hydrogen electrode (SHE) which arbitrarily defined as zero.

63. Pure metals are more corrosion resistant than commercial materials.
a) True
b) False
Answer: a
Explanation: In most of the cases of corrosion, pure metals are more corrosion resistant than commercial materials. This is due to the absence of galvanic effect and selective leaching in pure metals.

64. Which of the following are the types of metallic coatings that prevent corrosion?
a) Metal cladding
b) Electroplating
c) Metal coat extrusion
d) Metal cladding, electroplating and metal coat extrusion
Answer: d
Explanation: Corrosion is an electrochemical reaction that results in the degradation of a material. It can be prevented by various metal coating methods such as metal cladding, electroplating and metal coat extrusion.

65.What is the other name of galvanic corrosion?
a) Bi-metallic corrosion
b) Mono-metallic corrosion
c) Localized corrosion
d) Mono-metallic and localized corrosion
Answer: a
Explanation: Galvanic corrosion can be termed as bi-metallic corrosion or two-metal corrosion. This is because the driving force for current transfer and corrosion is the potential developed between the two metals.

66. Corrosion of less corrosion-resistant metal is usually increased and the attack of the more corrosion-resistant is decreased in galvanic corrosion.
a) True
b) False
Answer: a
Explanation: As galvanic corrosion is a bi-metallic corrosion, relatively less corrosion-resistant metal preferentially acts as anode and relatively high corrosion-resistant metal preferentially acts as a cathode. This increases attack on the less corrosion-resistant metal (anode) and decreases on high corrosion-resistant metal (cathode).

67. Which of the following is the driving force in galvanic corrosion?
a) Conductivity of electrolyte
b) Crystal structure of metals
c) The potential difference between the two metals
d) Temperature of electrolyte
Answer: c
Explanation: The principle driving force for current transfer and corrosion is the potential developed between the two metals. This potential difference can be altered by various factors such as conductivity of electrolyte and temperature of the electrolyte.

68. Which of the following will act as cathode and anode respectively in a dry-cell battery?
a) Zinc and carbon
b) Carbon and zinc
c) Magnesium and zinc
d) Zinc and ammonium chloride
Answer: b
Explanation: Battery is a combination of cells in which chemical energy is converted into electrical energy. Carbon (noble electrode) acts as cathode and zinc (active electrode) acts as an anode. Moist ammonium chloride is used as an electrolyte.

69. Which of the following is the primary characteristic of an electrolyte to form corrosion?
a) Electrical resistivity
b) Thermal resistivity
c) Thermal conductivity
d) Electrical conductivity
Answer: d
Explanation: Electrical conductivity is the primary characteristic of an electrolyte. Electrolyte is a medium to transfer electrons from anode to cathode, this results in corrosion. The conductivity of the electrolyte is one of the main factors in the regulation of corrosion.

70. What are the conditions to measure the standard reduction potential of metals against SHE?
a) 2 atm pressure, 25°C temperature, 2M concentration of H+
b) 2 atm pressure, 25°C temperature, 1M concentration of H+
c) 1 atm pressure, 25°C temperature, 1M concentration of H+
d) 1 atm pressure, 25°C temperature, 2M concentration of H+
Answer: c
Explanation: The conditions to measure the standard reduction potential of metal electrodes against standard hydrogen electrode (SHE) are 1 atmospheric pressure, 25°C temperature and 1 molarity concentration of H ions.

71. What is the abbreviation of EMF?
a) Electromagnetic force
b) Electromotive frequency
c) Electromotive force
d) Electrode motive force
Answer: c
Explanation: EMF is abbreviated as an electromotive force. It is defined as the potential difference between two points (cathode and anode) in a circuit. It is the cause of the flow of current in the circuit.

72. Which of the following electrolyte is used for the preparation of a general galvanic series?
a) Polluted seawater
b) Unpolluted river water
c) Polluted river water
d) Unpovlluted seawater
Answer: d
Explanation: Galvanic series is the most accurate prediction of galvanic relationships of metals. It is based on potential measurements and galvanic corrosion tests in unpolluted seawater. This includes metals and alloys along with their active and passive states.

73. Which of the following metal combination has a minimum galvanic effect?
a) Monel and copper
b) Inconel (passive) and Inconel (active)
c) 18-8 stainless steel (active) and 18-8 stainless steel (passive)
d) Titanium and lead
Answer: a
Explanation: The galvanic effect can be reduced by selecting close metal combinations. The position of a metal or an alloy in galvanic is mainly affected by its composition and its state (active or passive). Monel (70 Ni, 30Cu) and copper is the close metal combination, hence it has a minimum galvanic effect.

74. Which of the following is/are the reasons for the cause of crevice corrosion?
a) The stagnant solution in the holes and gasket surfaces
b) The stagnant solution in the lap joints and surface deposits
c) Dissimilar metal contact
d) The stagnant solution in the holes, gasket surfaces, lap joints, and surface deposits
Answer: d
Explanation: Crevice corrosion is a type of corrosion in which dissolution of metal is due to the presence of stagnant solution in the small gaps (crevice) such as holes, gasket surfaces, lap joints, and surface deposits, etc.

75. Which of the following type of corrosion is localized in nature?
a) Crevice corrosion
b) Galvanic corrosion
c) Uniform corrosion
d) Inter-granular corrosion
Answer: a
Explanation: Crevice corrosion is localized corrosion because it occurs only at discrete sites on the metal surface. This occurs due to the presence of a stagnant solution in crevices (small spaces). This crevice corrodes rapidly by cathodically protecting adjacent surfaces.

76. Which of the following is the other name of crevice corrosion?
a) Filiform corrosion
b) Deposit or gasket corrosion
c) Two-metal corrosion
d) Surface corrosion
Answer: b
Explanation: Crevice corrosion occurs due to the presence of a stagnant solution in the crevices. These crevices are formed due to the corrosion deposits or gaps at the metal-gasket interface. Thus, it is also called as deposit or gasket corrosion.

77. Which of the following metal is more susceptible to crevice corrosion?
a) Titanium
b) Hastelloy C
c) Stainless steel-430
d) Titanium and stainless steel
Answer: c
Explanation: Stainless steel-430 is highly prone to crevice corrosion. The reasons are as follows:
1. Large critical current density
2. Wide active-passive transitions
3. Limited passive region
5. Which of the following combination results in crevice corrosion?
a) Metal and absorbent gaskets
b) Continuous weld metals
c) Metal and non-absorbent gaskets
d) Single metal piece
Answer: a
Explanation: Metal and absorbent gasket combination results in the crevice corrosion. Absorbent gaskets absorb water vapor from surrounding and make them stagnant at the metal–gasket interface. This results in crevice corrosion.

78. Which of the following characteristics of the crevice is a must to act as a corrosion site?
a) It should be wide enough to permit liquid entry
b) It should be narrow enough to maintain a stagnant zone
c) It should be wide enough to avoid a stagnant zone
d) It should be wide enough to permit liquid entry and narrow enough to maintain a stagnant zone
Answer: d
Explanation: Crevice is a small volume region formed between the interface of metal and gaskets. It acts as a corrosion site if is wide enough to permit liquid entry and narrow enough to maintain a stagnant zone.

79. What is the primary condition regarding the velocity of an electrolyte to form crevice corrosion?
a) The velocity of the electrolyte should be greater than 10cm/s
b) The velocity of the electrolyte should be less than 10cm/s
c) The velocity of the electrolyte should be equal to 10cm/s
d) The stagnant electrolytic solution should be present
Answer: d
Explanation: Crevice corrosion occurs due to the presence of stagnant electrolytic solution in the crevices. It acts at the corrosion sites and it results in the formation of localized corrosion. An increase in the velocity of the electrolyte decreases the extent of crevice corrosion.

80. The difference in metal ion or oxygen concentration between the crevice and its surroundings is the main reason for crevice corrosion.
a) True
b) False
Answer: a
Explanation: Crevice corrosion is mainly occurred due to the difference in metal ion or oxygen concentration between the crevice and its surroundings. This is due to the unavailability of oxygen in the crevice, this results in the dissolution of metal in a crevice by protecting adjacent surface cathodically.

81. Erosion corrosion accelerates the rate of attack on a metal because of relative movement between corrosive fluid and the metal surface.
a) True
b) False
Answer: a
Explanation: Erosion corrosion is one of the types of corrosion that accelerates the rate of deterioration or attack on a metal because of the relative movement of corrosive fluid and the metal surface.

82. Which of the following type of directional patterns usually exhibit by erosion-corrosion?
a) Grooves
b) Waves
c) Rounded holes
d) Grooves, waves and rounded holes
Answer: d
Explanation: Erosion corrosion results in wear or abrasion of the surface of the metal. It is characterized in appearance by grooves, gullies, waves, rounded holes, and valleys.

83. Which of the following type of corrosion is depicted in the given figure?

a) Uniform corrosion
b) Erosion corrosion
c) Galvanic corrosion
d) Selective leaching
Answer: b
Explanation: Erosion corrosion is depicted in the given figure. Erosion corrosion accelerates the rate of deterioration or attack on a metal because of the relative movement of corrosive fluid and the metal surface.

84. Erosion corrosion results when the protective oxide films are damaged and the metal or alloy are attacked at a rapid rate.
a) True
b) False
Answer: a
Explanation: As the relative movement of the corrosive solution and the surface of the metal increases the intensity of erosion-corrosion increases. At higher velocities, it results in the damage or worn out of oxide film and it attacks the metal rapidly.

85. Which of the following metals is/are susceptible to erosion-corrosion?
a) Aluminum
b) Lead
c) Stainless steel
d) Aluminum, lead and stainless steel
Answer: d
Explanation: Aluminum, lead, copper, and stainless steel are the metals that are susceptible to erosion-corrosion. Because these metals mainly depend on their oxide film for its corrosive resistance.

86. Which of the following type of equipment is/are highly prone to erosion-corrosion?
a) In piping arrangements at elbows and bends
b) Measuring devices such as orifice and turbine blades
c) In piping arrangements at straight lines
d) In piping arrangements at elbows and bends and measuring devices such as orifice and turbine blades
Answer: d
Explanation: Erosion corrosion can be affected by the relative velocity of the corrosive solution and metal surface and along with impingement velocity at the edges and turnings. In piping arrangements at elbows and bends and measuring devices such as orifice and turbine blades are the equipment that is prone to erosion-corrosion.

87. Which of the following is/are the characteristics of oxide film that exhibits better resistance to erosion-corrosion?
a) Hard
b) Dense
c) Adherent
d) Hard, dense and adherent
Answer: d
Explanation: Erosion corrosion is the type of corrosion that results in mechanical damage of the metal due to the high velocities of corrosive solutions. And a hard, dense, and adherent oxide film can exhibit better resistance to erosion-corrosion.

88. Which of the following characteristics of titanium, makes it resistant to erosion-corrosion?
a) Stability of titanium oxide
b) Instability of titanium oxide
c) The low reactivity of titanium
d) The low reactivity of titanium and instability of titanium oxide
Answer: a
Explanation: Titanium is a reactive metal but is resistant to erosion-corrosion in many environments because of the stability of the titanium oxide (TiO2) film. It reforms its oxide layer within a fraction of seconds after wearing out.

89. Which of the following metal is resistant to seawater, chlorides, and fuming nitric acid?
a) Aluminum
b) Lead
c) Titanium
d) Stainless steel
Answer: d
Explanation: Titanium is highly resistant to seawater, chlorides, and fuming nitric acid. It is also resistant to erosion-corrosion because of its high reactivity and stability of oxide film.

90. Which of the following environmental factor plays an important role in erosion-corrosion?
a) Velocity
b) Corrosive concentration
c) pH of the environment
d) Relative humidity of the atmosphere
Answer: a
Explanation: Erosion corrosion accelerates the rate of attack on a metal because of relative movement between corrosive fluid and the metal surface. It increases as the velocity of the corrosive solution increases.

91. Define critical velocity regarding erosion-corrosion.
a) Velocity at which erosion-corrosion starts
b) Velocity at which erosion-corrosion stops
c) Velocity after which erosion-corrosion increases exponentially
d) Velocity after which erosion-corrosion decreases exponentially
Answer: c
Explanation: Critical velocity is the velocity after which the erosion-corrosion increases exponentially. Case 1 (velocity less than critical velocity):
Erosion corrosion increases linearly with increase with velocity.
Case 2 (velocity greater than critical velocity):
Erosion corrosion increases exponentially with increase with velocity.

92. Which of the following metal shows a decrease in corrosion attack with an increase in velocity in fuming nitric acid?
a) Aluminum
b) Carbon steel
c) Stainless steel 347
d) Copper
Answer: c
Explanation: Under stagnant conditions, stainless steel 347 in nitric acid is attacked autocatalytically because of the formation of nitrous acid as a cathodic reaction product. An increase in velocity sweeps away the corrosive nitrous acid in the environment.

93. What is the abbreviation of SCC regarding corrosion?
a) Stress-corrosion cracking
b) Stress-cracking corrosion
c) Stress-corrosion contact
d) Stress-contact corrosion
Answer: a
Explanation: SCC can be abbreviated as stress-cracking corrosion. It is referred to the simultaneous action of corrosion and stress on a metal structure. Tensile stress is the most common stress that encounters in the industrial world.

94. Stress-corrosion cracking occurs due to the simultaneous presence of tensile stress and a specific corrosive medium.
a) True
b) False
Answer: a
Explanation: Stress–corrosion cracking occurs due to the simultaneous presence of tensile stress either is caused by residual or external stress and a specific corrosive medium. Residual stress is caused due to welding, cold working, etc.

95. Which of the following is/are the classic examples of stress-corrosion cracking?
a) Season cracking of brass
b) Caustic embrittlement of steel
c) Season cracking of brass and caustic embrittlement of steel
d) Neither season cracking of brass nor caustic embrittlement of steel
Answer: c
Explanation: The two main classic examples of stress-corrosion cracking are:
i. Season cracking of brass
ii. Caustic embrittlement of steel.

96. What is meant by season cracking of brass?
a) Stress-corrosion cracking failure of brass cat ridge cases due to ammonia
b) Stress-corrosion cracking failure of brass cat ridge cases due to caustic soda
c) Stress-corrosion cracking failure of brass cat ridge cases due to caustic soda and ammonia
d) Stress-corrosion cracking failure with brittle fracture
Answer: a
Explanation: Season cracking refers to the stress-corrosion cracking failure of brass cat ridge cases. The main important environmental component in season cracking is ammonia, which results from the decomposition of organic matter.

97. What is meant by caustic embrittlement of steel?
a) Failure of cold-worked rivets by a brittle fracture in the presence of ammonia
b) Failure of cold-worked rivets by a brittle fracture in the presence of caustic soda
c) Failure of cold-worked rivets by a brittle fracture in the presence of caustic soda and ammonia
d) Failure of cold-worked rivets by the cup and cone fracture in the presence of caustic soda
Answer: b
Explanation: Explosions of riveted boilers that occurred in early steam-driven locomotives are due to the cold working during the operation. Hence, brittle fracture in the presence of caustic resulted in caustic embrittlement.

98. In which of the following environments that stainless steel will undergo stress-corrosion cracking?
a) Chlorides
b) Caustics
c) Ammonia
d) Chlorides and caustics
Answer: d
Explanation: Stainless steel undergoes stress-corrosion cracking in chlorides and caustics. They do not crack in ammonia, sulfuric acid, nitric acid, acetic acid, and pure water.

99. Which of the following is/are the most important variables that affect stress-corrosion cracking?
a) Temperature
b) Metal composition
c) Type and amount of stress applied
d) Temperature, metal composition, and type and amount of stress applied
Answer: d
Explanation: The most important variables that affect stress-corrosion cracking are:
i. Temperature
ii. Metal composition
iii. Corrosive solution composition
iv. Type and amount of stress applied
v. Design of metal structure.

100. Which of the following alloy in which both intergranular and trans-granular cracking occurs?
a) High-nickel alloys
b) iron-chromium alloys
c) Brasses
d) High-nickel alloys, iron-chromium alloys, and brasses
Answer: d
Explanation: Stress-corrosion cracking can be intergranular and trans-granular cracking. Alloys such as high-nickel alloys, iron-chromium alloys, and brasses often crack both in intergranular and transgranular manner.

101. Define Threshold stress regarding stress-corrosion cracking.
a) The maximum stress at which the specimen ruptures
b) The maximum stress required to prevent cracking
c) The minimum stress required to prevent cracking
d) The minimum stress at which cracking starts
Answer: c
Explanation: Increasing stress decreases the time before cracking occurs. Threshold stress is the minimum stress required to prevent cracking. It depends on temperature, alloy composition, and environment composition.

102. As stress-corrosion cracks penetrate the material, the cross-sectional area gets reduced under constant tensile load.
a) False
b) True
Answer: b
Explanation: Stress-corrosion cracking is the simultaneous attack of corrosion and stress. A stress-corrosion crack penetrates the material; the cross-sectional area gets reduced under constant tensile stress.

103. Which of the following is/are the environments that cause stress-corrosion cracking to titanium?
a) Red fuming nitric acid
b) Methanol-HCl
c) Nitrogen tetroxide (N2O4)
d) Red fuming nitric acid, methanol-HCl, and nitrogen tetroxide
Answer: d
Explanation: Stress-corrosion cracking is the simultaneous action of stress and corrosive environment on a metal. Red fuming nitric acid, methanol-HCl, and nitrogen tetroxide are the environments that may cause stress-cracking corrosion.

104. Which of the following is/are the metallurgical factors that affect stress-corrosion cracking?
a) Chemical composition
b) Distribution of precipitates
c) Dislocation interactions
d) Chemical composition, distribution of precipitates and dislocation interactions
Answer: d
Explanation: Metallurgical factors that affect stress-corrosion cracking are:
i. Average chemical composition
ii. Preferential orientation of grains
iii. Distribution of precipitates
iv. Dislocation interactions
v. Degree of metastability.

105. Which of the following materials will undergo Corrosion?
a) Metals only
b) Metals and Non-metals
c) Metals, Non-metals, Ceramics and Plastics
d) Metals, Non-metals, Ceramics, Plastics and Rubbers
Answer: d
Explanation: Corrosion is defined as the destruction or deterioration of a material because of reaction with its environment. Every material in the universe will undergo corrosion but it varies in time and form. Any Physical, Chemical or Mechanical deviation of the original material is known as Corrosion.

106. Corrosion of material by furnace gases is classified as _____
a) wet corrosion
b) dry corrosion
c) galvanic corrosion
d) crevice corrosion
Answer: b
Explanation: Dry corrosion occurs in the absence of moisture usually by vapors and gases whereas the wet corrosion, galvanic corrosion and crevice corrosion occurs in aqueous state or in the presence of moisture.

107. Which of the following is an example of wet corrosion?
a) Corrosion of metal in the water
b) Corrosion of iron in the presence of anhydrous calcium chloride
c) Corrosion of titanium in dry chlorine
d) Corrosion due to furnace gases
Answer: a
Explanation: Wet corrosion occurs when the liquid is present. This usually involves aqueous solutions or electrolytes as corrosive mediums. Corrosion of iron in the presence anhydrous calcium chloride, by furnace gases and by dry chlorine are classified under dry corrosion.

108. Corrosion maintenance is vital in _____ industries.
a) paper
b) petroleum
c) plastic toy
d) both petroleum and paper
Answer: d
Explanation: The operating conditions in both the petroleum and paper industry are mainly in aqueous state with various chemicals in it. Hence these are likely prone to various electrochemical reactions which causes corrosion. Maintenance works include periodic inspection and replacements of partially corroded parts. It minimizes costly catastrophic failures, unscheduled down time, resulting in increased production and revenue.

109. Which of the following subjects are important in understanding and controlling corrosion?
a) Thermodynamics
b) Electrochemistry
c) Both Thermodynamics and Electrochemistry
d) Material Characterization
Answer: c
Explanation: Thermodynamic studies and calculations indicate the spontaneous direction of the reaction. The thermodynamic stability of corrosion product is relatively higher than reactant. Whereas the electrochemistry deals with electrode kinetics of the reaction.

110. Deterioration of paint and rubber by sunlight or chemicals is not a corrosion.
a) True
b) False
Answer: b
Explanation: Any deviation in the physical, chemical and mechanical properties of a material is considered as corrosion. Here we can notice physical change so it is a corrosion.

111. Which of the following is an incorrect statement?
a) Corrosion is an irreversible process
b) Corrosion is a non-spontaneous process
c) Corrosion is a degradation process
d) Corrosion is a spontaneous process
Answer: b
Explanation: Corrosion is a spontaneous process which results in degradation of materials and it is irreversible in nature. Spontaneous reaction is a reaction which results in the formation of stable products from unstable without need of any external energy.

112. Which of the following is considered as high corrosive resistant material?
a) Mild steel
b) Cast iron
c) Zinc
d) Stainless steel
Answer: d
Explanation: Corrosion resistant material is the material which has less corrosion rate in a particular atmosphere without much degradation. Stainless steel (an alloy of iron, chromium, nickel) is considered as corrosion resistant material. This is because it forms chromic oxide layer over its surface to avoid physical contact with the outside environment.

113. Corrosion involves _______ reactions.
a) oxidation
b) reduction
c) displacement
d) both oxidation and reduction
Answer: d
Explanation: Corrosion is an electrochemical reaction. It occurs by therelease and gain of electrons from various species which are termed as oxidation and reduction respectively. It can be observed with change in the oxidation state of the species.

114. Which of the following are necessary in the process of corrosion?
a) Anode
b) Cathode
c) Electrolyte
d) Anode, Cathode and Electrolyte
Answer: d
Explanation: Corrosion occurs by the creation of electrochemical cell which includes a cathode, an anode and an electrolyte. A high reduction potential will act as cathode and other will acts as anode preferentially and electrolyte is needed to transfer ions between these two electrodes.

115. If a metal undergoes uniform corrosion it becomes _____
a) thinner
b) thicker
c) perforated
d) thicker and perforated
Answer: a
Explanation: Uniform corrosion is the most common form of corrosion. It is characterized by an electrochemical reaction that proceeds uniformly over the entire exposed surface. Thus, the metal becomes thinner.

116. Which theory explains the oxidation of metals?
a) Collison theory
b) Molecular orbital theory
c) Wagner’s theory
d) Mixed potential theory
Answer: c
Explanation: Wagner’s theory states that the oxidation of metal is electrolytic in nature and the rate of oxidation is determined by the electrical properties of the corrosion product.

117. What is the mechanism of dry corrosion?
a) Absorption
b) Electrochemical
c) Differential solubility
d) Both electrochemical and differential solubility
Answer: a
Explanation: Dry corrosion occurs in the absence of a liquid phase. Vapors and gases are usually the corrodents. These will hit and adsorbed on the metal surface to form corrosion. So dry corrosion can be explained by an absorption mechanism.

118. Corrosion of iron takes place even in the solid ice.
a) True
b) False
Answer: b
Explanation: Though ice is the solid form of water but it doesn’t conduct electrons. The function of an electrolyte is to transfers ions from one electrode to another. Thus, given statement is false. Corrosion needs an anode, a cathode and a conductive electrolyte.

119. What are the factors that affect corrosion?
a) Temperature
b) Humidity
c) Conductance of the corroding medium
d) Temperature, humidity and conductance of the corroding medium
Answer: d
Explanation: The main factors that affect the rate of corrosion includes the effect of pH, temperature, humidity, conductance of the corroding medium, oxygen concentration, presence of impurities. These factors are based on the nature of environment.

120. _______ is a chemical substance which reduces the corrosion rate.
a) Corrosion inhibitor
b) Corrosion initiator
c) Electrolyte
d) Corrosive medium
Answer: a
Explanation: An inhibitor is a substance that, when added in small concentrations to an environment, decreases the corrosion rate.
Following are the types of inhibitors:
i. Adsorption-type
ii. Hydrogen-evolution poisons
iii. Scavengers
iv. Vapor-phase

1. The principles of green chemistry include eliminating ________ treatments.
a) Costly
b) Harmful
c) Hard
d) Easy
Answer: a
Explanation: The principles of green chemistry include eliminating costly treatments. It makes the reactions with less cost and no toxic materials.

2. One of the principles of green chemistry says that to produce _______ goods.
a) Harmful
b) Commercial
c) Safer
d) Most used
Answer: c
Explanation: One of the principles of green chemistry says that the produced goods must be safe. That means the goods must be not harmful for environment.

3. After the use of chemicals, we must ______ them properly.
a) Use
b) Reuse
c) Dispose
d) Store
Answer: c
Explanation: After the use of chemicals, we must dispose them properly. The empty chemical containers should not be reused because they are toxic and if they are not disposed properly, they create the environmental pollution.

4. Green chemistry applies across the __________ of a chemical product like design, manufacture and use.
a) Life cycle
b) Properties
c) Uses
d) Efficiency
Answer: a
Explanation: Green chemistry applies across the life cycle of a chemical product like design, manufacture and use. It says that manufacturing should be done without any pollution.

5. We must use feedstock derived from annually renewable resources or from _______
a) Chemicals
b) Organic compounds
c) Abundant waste
d) Plants
Answer: c
Explanation: We must use feedstock derived from annually renewable resources or from abundant wastes. The wastes are utilised back.

6. Green chemistry improves __________ of chemical manufacturers.
a) Competitiveness
b) Easiness of production
c) Services
d) Chemicals
Answer: a
Explanation: Green chemistry improves competitiveness of chemical manufacturers. The products are of low cost and good quality. So, it improves the competition.

7. It reduces the use of _________
a) liquid fuels
b) Energy
c) Gaseous fuels
d) Solid fuels
Answer: b
Explanation: It reduces the use of the energy. The less consumption of energy also reduces the cost of production. So, the product will be available at low costs.

8. It reduces the ______ and protects the environment.
a) Pollution
b) Temperature
c) Air
d) Water
Answer: a
Explanation: It reduces pollution and protects the environment. By green synthesis, the products that are non-hazards to the nature are produced. So, no pollution takes place.

9. According to the green chemistry, the chemical involved in the production must be ________
a) Non toxic
b) Toxic
c) Highly toxic
d) Produces the toxic by products
Answer: a
Explanation: According to the green chemistry, the chemical involved in the production must be nontoxic.

10. The green synthesis methods should have _________
a) Low efficiency
b) High harmful products
c) Low energy requirements
d) Low atom efficiency
Answer: c
Explanation: The green synthesis methods should have high efficiency, less harmful products, low energy requirements and high atom efficiency.

11. Green chemistry is also called as ________
a) Life chemistry
b) Environmental chemistry
c) Organic chemistry
d) Sustainable chemistry
Answer: d
Explanation: Green chemistry deals mainly about the pollution variation in the environment and sustainance of the plants and animals and mankind in a healthy manner. So, this is also called as the sustainable chemistry.

12. An ideal solvent facilitates the __________
a) Mass transfer
b) Dissolving property
c) Combustion
d) Titration
Answer: a
Explanation: An ideal solvent facilitates the mass transfer. Water is called as universal solvent. Any solute can be dissolved in water and facilitates for mass transfer.

13. A desirable green solvent should be __________
a) Costly
b) Toxic
c) Readily available
d) Synthetic
Answer: c
Explanation: A desirable green solvent should be readily available. The desirable green solvent should be cheaper. It should be safe and nontoxic. It should be natural.

14. The green solvent maximises the atom _________
a) Molecular weight
b) Electronic configuration
c) Velocity
d) Efficiency
Answer: d
Explanation: The green solvent maximises the atom’s efficiency. For example benzene can be replaced by the toulene, cyclo hexane instead of carbon tetrachloride can be replaced.

15. What is the percentage atom utilisation?
a) (mole wt of desired product\100)/mole wt of (desired producttotal product)
b) (mole wt of desired product\100)/mole wt of (desired product)
c) (mole wt of desired product\100)/mole wt of (desired productused product)
d) (mole wt of desired product\100)/mole wt of (desired productby product)
Answer: d
Explanation: The percentage atom utilisation is given by (mole wt of desired product*100)/mole wt of (desired productby product). Here, mole wt indicates the molecular weight. The by product can be used to re generate the reaction.

16. The __________ reactions involves reorganisation of the atoms of the molecules.
a) Addition reactions
b) Rearrangement reactions
c) Reorganised reactions
d) Elimination reactions
Answer: b
Explanation: The rearrangement reactions involve reorganisation of the atoms of the molecules. Because, neither elimination, substitution nor addition of atoms is not taking place. So, the molecule undergoes the rearrangement reactions.

17. C2H4 1/2 O2 → C2H4O(Ethylene oxide). This reaction will takes place under presence of catalyst. Find out the %atom economy.
a) 25%
b) 50%
c) 75%
d) 100%
Answer: d
Explanation: Ethylene reacting with oxygen in the presence of catalyst forms the ethylene oxide. The %atom economy can be calculated by (formula wt of atoms utilized/formula wt of reactants)100. The formula weight of the reactants is 44 and atoms utilized are also 44. So, the %atom economy is 100%.

18. _________ are greener than the conventional methods.
a) Micro waves
b) Electromagnetic waves
c) Ultra violet waves
d) Radio waves
Answer: a
Explanation: Micro waves are greener than the conventional methods in organic synthesis without solvents. The wide range of micro wave chemistry is extended recently too many aspects of organic synthesis.

19. Self thermo regulated systems are called as __________
a) Green methodologies
b) Green synthesis
c) Green principles
d) Green concepts
Answer: a
Explanation: The self thermo regulated systems are called as green methodologies. Soluble polymers are another example that comes under green methodologies.

20. _________ is the fundamental advantage of the sono chemistry in organic synthesis without solvents.
a) High yields
b) High energy requirements
c) Use of solvents
d) High wastes
Answer: a
Explanation: The yield should be high. This is one of the advantages of the sono chemistry in organic synthesis without solvents. The other fundamental advantages are low energy requirements, no use of solvents and low wastes.

21. The atom economy obtained for green synthesis is in the range of _________
a) 62-70%
b) 72-82%
c) 40-50%
d) 90-100%
Answer: b
Explanation: The atom economy obtained for green synthesis is in the range of 72-82%. If the reaction is rearrangement reaction then the % of atom economy is mostly 100%.

22. Micro fluid reactor will minimise _________
a) Solvent waste
b) Efficiency
c) Number of molecules
d) Number of collisions
Answer: a
Explanation: Micro fluid reactor is used to minimise the solvent waste. When the reaction takes place there will be a product sometimes useful by sometimes unnecessary. Such waste must be reduced.

23. Green synthesis method is ________ than the conventional method.
a) More costlier
b) More efficient
c) Slower
d) Less efficient
Answer: b
Explanation: Green synthesis method is more efficient than the conventional method. So, the green synthesis method is selected now a days.

24. In petrochemical industry, both in conventional method and green synthesis what is the first product obtained?
a) 2-ethyl benzene
b) Ethanol
c) Methyl methacrylate
d) 2-methyl propyl benzene
Answer: d
Explanation: In petrochemical industry, both in conventional method and green synthesis, 2-methyl propyl benzene is the first product obtained. All the other elements may produce later in some case.

25. In conventional method _________ is used.
a) Nacl
b) Alcl3
c) Na2SO4
d) H2SO4
Answer: b
Explanation: In the conventional method AlCl3 is used. All the other elements are not supposed to be used in these reactions.

26. What is the starting material for nylon 6-6 is _________
a) Acetic anhydride
b) 2-methyl propyl benzene
c) Adipic acid
d) Nitric acid
Answer: c
Explanation: The starting material for producing the nylon 6-6 is adipic acid. It is prepared from poly condensation of hexaethylene diamine and adipic acid.

27. In green synthesis by avoiding harmful by products the catalyst used is _________
a) Tungsten
b) Benzene
c) Cyclo hexane
d) Adipic acid
Answer: a
Explanation: In green synthesis by avoiding harmful by products the catalyst used is Tungsten. All the other are cyclic elements. They produce some harmful materials as they are carbon compounds.

28. In green synthetic methods, the high quality product with no ________ are produced.
a) Good products
b) Catalyst
c) Reaction
d) Contamination
Answer: d
Explanation: In green synthetic methods, the high quality product with no contamination is produced. The main aim is to avoid contamination or pollution.

29. The green synthesis methods should have _______
a) Low efficiency
b) High harmful by products
c) Low energy requirements
d) Low atom efficiency
Answer: c
Explanation: The green synthesis mainly gives the good product with less cost and more standard and no toxic materials. So, the energy required will be less.

30. The di-basic acid is used in its ________
a) Impure form
b) Pure form
c) Solid state
d) Liquid form
Answer: b
Explanation: The di-basic acid is used in its pure form. Its melting point is 152.1oC. In preparation of the nylon 6-6, the first step is to prepare the salt.

1 : When incomplete combustion loss is high, the flue gas analysis shows large amount of
a.CO2
b.CO
c.O2
Answer : b

2 : The gas which contributes maximum to the heating value of natural gas is
a.CO
b.CO2
c.H2
d.CH4
Answer : d

3 : The temperature at which plastic layer formation takes place during carbonisation of coal varies from __________ °C.
a.100 to 150
b.350 to 450
c.550 to 650
d.700 to 850
Answer : b

4 : Yield of coke oven gas in low temperature carbonisation of coal is about __________ Nm3 /ton of dry coal.
a.60
b.160
c.500
d.750
Answer : b

5 : Temperature of preheated air used for the transportation of pulverised coal through pipes to the burner of a boiler furnace is restricted to a maximum limit of about 300° C to avoid the
a.requirement of large volume combustion chamber.
b.risk of explosion.
c.chances of clinker formation.
d.incomplete combustion of coal.
Answer : b

6 : Adiabatic flame temperature of a fuel is dependent on the initial temperature of
a.fuel
b.air
c.both (1) & (2)
d.neither (1) nor (2)
Answer : c

7 : Which of the following gaseous fuels has the lowest calorific value ?
a.Gobar gas
b.Refinery gas
c.Converter gas
d.Blast furnace gas
Answer : d

8 : Which of the following is not a by-product recovered in a high temperature coal carbonisation plant ?
a.Benzol
b.Pitch-cresosote mixture (PCM)
c.Napthalene
d.Ethylene
Answer : d

9 : Pensky-Marten apparatus is used for those oils, whose flash points are __________ °F.
a.<120
b.>120
c.<90
d.90-110
Answer : b

10 : In high temperature carbonisation of coal compared to low temperature carbonisation
a.yield of ammonia is less
b.aromatic content of tar is low.
c.H2 content in the coke oven gas is more.
d.calorific value of the coke oven gas is lower.
Answer : c

11 : Fuel gases containing hydrocarbons (ie.g. coke oven gas) are not preheated before burning, mainly because
a.the hydrocarbons crack thereby choking and fouling the heat transfer surface by carbon soot.
b.it reduces its calorific value tremendously.
c.it reduces its flame temperature tremendously.
d.there are chances of explosion during preheating.
Answer : a

12 : Which of the following is the most reactive (as regards the formation of CO + H2 from C + H2O) ?
a.Blast furnace coke
b.Low temperature coke
c.Anthracite coal
d.Sub-bituminous coal
Answer : b

13 : Calorific value of coal middling generated in coal washeries during washing of coal may be around __________ Kcal/kg.
a.1000
b.4000
c.6000
d.8000
Answer : b

14 : Flue gas discharge velocity through chimney of a big thermal power plant may be around __________ m/sec.
a.0.5
b.10
c.50
d.500
Answer : b

15 : Which of the following is used for making the explosive ‘TNT’ ?
a.Benzol
b.Toluene
c.Pyridine
d.Cerosote
Answer : b

16 : Gray King Assay and Swelling Index of a coal is a measure of its
a.swelling characteristics.
b.abradability.
c.agglutinating properties.
d.resistance to impact breakage.
Answer : a

17 : Explosion limit of blast furnace gas is 37 to 71% gas in gas-air mixture. It means that the blast furnace gas will explode when burnt in a confined space, if its concentration in the gas-air mixture is __________ percent.
a.< 37%
b.>71%
c.in between 37 & 71%
d.none of these
Answer : c

18 : Prime coking coal is always blended with medium or non- coking coal before ear-bonisation
a.to check against its excessive swelling during heating, which may exert high pressure and damage coke oven walls.
b.because, it alone produces unreactive coke.
c.both (a) and (b).
d.neither (a) nor (b).
Answer : c

19 : Actual flame temperature is always lower than the adiabatic flame temperature, because there is
a.no possibility of obtaining complete combustion at high temperature.
b.always loss of heat from the flame.
c.both (a) and (b).
d.neither (a) nor (b).
Answer : c

20 : Coke oven gas consists mainly of
a.H2, & CH4
b.CO, & CO2
c.H2, & CO
d.CH4, & CO
Answer : a

21 : Higher percentage of ash in coal meant for the production of metallurgical grade coke
a.decreases the hardness of coke.
b.decreases the abrasion resistance of coke.
c.causes brittleness in steel.
d.none of these.
Answer : d

22 : Combustion of pulverised coal as compared to that of lump coal
a.develops a non-luminous flame.
b.develops a low temperature flame.
c.can be done with less excess air.
d.provides a lower rate of heat release.
Answer : c

23 : “Wobbe index’ is a characteristic of
a.solid fuels
b.gaseous fuels
c.liquid fuels
d.fat coals
Answer : b

24 : A coal with high ash content is undesirable, as
a.it is abrasive to the coal pulveriser (ie.g. ball mill) and the combustion chamber.
b.the ash in molten condition gets absorbed in the pores of the refractory lining of the furnace and causes its spalling due to different co-efficient of expansion/contraction of the refractory and the ash.
c.the ash retains the sulphur & phosphorus and thus affects the quality of products in metallurgical furnace apart from increasing the slag volume. Besides, it may fuse and stick to the boiler tubes thereby reducing the heat transfer.
d.all (a), (b) and (c).
Answer : d

25 : Presence of free moisture in coal during its high temperature carbonisation
a.reduces the coking time.
b.protects the volatile products from pyrolysis (cracking) in the presence of hot coke and hot oven walls.
c.increases the loss of fine coal dust from the ovens when charging.
d.none of these.
Answer : b

26 : A coal having high amount of volatile matter
a.would require smaller combustion chamber.
b.produces very little of tar and gas on carbonisation.
c.ignites easily and burns with long smoky flame.
d.all (a), (b) and (c).
Answer : d

27 : Carbon Content by weight in air dried wood may be about __________ percent.
a.10
b.25
c.50
d.80
Answer : c

28 : Which of the following accentuates clinker-ing trouble on furnace grate burning coal ?
a.Low reactivity of carbonised residue containing high proportions of iron & sulphur.
b.Low forced draught and fuel bed temperature.
c.Thick fire bed and preheated primary air.
d.All (a), (b) and (c).
Answer : d

29 : Natural draught produced by a chimney depends upon the
a.density of the chimney gases.
b.height of the chimney.
c.both (a) and (b).
d.neither (a) nor (b).
Answer : c

30 : Gross & net calorific value is the same for
a.blast furnace gas
b.coke oven gas
c.L.D. converter gas
d.none of these
Answer : c

31 : Pick out the wrong statement.
a.LPG is also used as fuel for automobiles & small furnaces and for cutting & welding of metals.
b.The minimum temperature, at which a petroleum oil vapor catches fire and continues to burn, is called its flash point.
c.Each ton of petroleum oil on distillation produces about 30-50 Nm3 of gas.
d.Maximum yield of naphthalene is obtained on distillation of crude oil.
Answer : b

32 : Stack heat losses can be minimised by
a.controlling the excess air.
b.oxygen enrichment of combustion air.
c.using low c.v. fuels.
d.maintaining proper draft in the furnace.
Answer : a

33 : Laboratory gas is obtained by the cracking of
a.gasoline
b.diesel
c.fuel oil
d.kerosene
Answer : d

34 : Bituminous coal
a.ignites less easily than anthracite.
b.is generally coking.
c.burns with smoky yellow flame.
d.both (b) and (c).
Answer : d

35 : Ratio of primary air to secondary air increases with increase in the rank of coal, because the
a.high rank coals have higher amount of volatile matter.
b.ratio of fixed carbon to volatile matter increases.
c.oxygen content progressively decreases.
d.calorific value of the coal increases.
Answer : b

36 : Junker’s calorimeter is used to determine the calorific value of
a.pulverised coal
b.gaseous fuels
c.fuel oil
d.none of these
Answer : b

37 : Combustion reaction of fuels is a/an __________ reaction.
a.auto catalytic
b.exothermic
c.endothermic
d.none of these
Answer : b

38 : Improper storage condition results in the weathering of coal and spontaneous combustion, which increases its
a.caking index.
b.yield of carbonised products.
c.friability & oxygen content.
d.calorific value.
Answer : c

39 : Which of the following constituents of coal is the most important in the production of coke?
a.Moisture
b.Ash
c.Volatiles
d.Carbon
Answer : d

40 : High temperature in gasification of coal favours
a.high production of CO2.
b.low production of CO2.
c.high production of CO.
both (b) and (c).
Answer : d

41 : Which of the following is not used as a binder in coal briquetting ?\
a.Tar
b.Molasses
c.Pitch
d.Line
Answer : d

42 : Size of blast furnace grade coke is __________ mm.
a.25-80
b.0-15
c.15-25
d.>100
Answer : a

43 : Presence of __________ in a dry gaseous fuel does not contribute to its calorific value.
a.sulphur
b.oxygen
c.hydrogen
d.carbon
Answer : b

44 : The internal energy of the combustion products is __________ compared to that of reactants.
a.more
b.less
c.equal
d.more or less ; (depends on the state of fuel.)
Answer : b

45 : Which of the following is not a product of tar distillation ?
a.Phenol & naphthalene
b.Benzol & pitch
c.Anthracene & creosote
d.None of these
Answer : d

46 : Higher efficiency in the combustion of solid fuel can not be achieved by
a.proper fuel preparation.
b.keeping the flue gas exhaust temperature very high.
c.adopting efficient-fuel firing technique & equipment.
d.supplying correct quantity of combustion air.
Answer : b

47 : A coal containing very high percentage of durain is called __________ coal.
a.bright
b.splint
c.non-banded
d.boghead
Answer : b

48 : During combustion of gaseous fuels, deficiency of air
a.lengthens the flame.
b.tends to shorten the flame.
c.does not affect the flame length.
d.increases the flame temperature.
Answer : a

49 : Gross and net calorific value of a fuel will be the same
a.if its ash content is zero.
b.ifits carbon content is very low.
c.if its hydrogen/hydrogen compound content is zero.
d.under no circumstances.
Answer : c

50 : Low temperature carbonisation
a.is mainly for producing the smokeless domestic coke.
b.is meant for the production of ‘metallurgical coke’.
c.produces higher quantity of gas than high temperature carbonisation.
d.produces less quantity of tar than high temperature carbonisation.
Answer : a

51. In presence of which gas is the fuel burnt to generate energy in the form of heat?
a) Oxygen
b) Hydrogen
c) Methane
d) Nitrogen
Answer: a
Explanation: The fuel is burnt in the presence of oxygen to generate energy in the form of heat. This heat energy can be used for electrical power generation in steam power plants and for propelling ships, automobiles and locomotives, etc.

52. Which are the main constituents of fuel from given options?
a) Carbon and Nitrogen
b) Oxygen and Hydrogen
c) Carbon and Hydrogen
d) Helium and Oxygen
Answer: c
Explanation: Carbon and Hydrogen are the main constituents of a fuel. In addition to them, fuel also contains sulfur, oxygen and nitrogen in minimal quantities. Depending on the fuel, the percentage of carbon ranges from 50-95%, hydrogen (H2) 2-6%, oxygen (O2) 2-4%, sulfur (S2) 0.5-3% and Nitrogen (N) 5-7%. A solid fuel may also contain 2-30% ash. In a fuel carbon, hydrogen and sulfur are combustible elements whereas nitrogen and ash are incombustible elements. Since the major combustible elements in fuel are carbon and hydrogen it can also be called as Hydrocarbon fuel.

53. Which fuel is used widely in steam power plants?
a) Oil
b) Gas
c) Coal
d) Petroleum
Answer: c
Explanation: Coal is the oldest form of fuel and is still used in a large scale throughout the world by steam power plants as well as all power generation plants. Coal is a heterogeneous compound and its constituents are always carbon, hydrogen, oxygen, sulfur, nitrogen and certain mineral non combustibles.

54. What is the phenomenon of the formation of coal called?
a) Metamorphism
b) Diagenis’
c) Photosynthesis
d) Protolith
Answer: a
Explanation: The phenomenon by which the buried vegetation consisting wood, grass, shrubs etc, transformed into coal is known as metamorphism. The nature of coal will depend upon the type of vegetation buried and nature and duration of metamorphism. There are different types of metamorphism namely contact metamorphism, regional metamorphism, cataclastic metamorphism, hydrothermal metamorphism, burial metamorphism and shock metamorphism.

55. On what basis is the coal classified?
a) Period of formation
b) Depending on capacity to burn
c) Region/area where is it formed
d) Physical and chemical composition
Answer: d
Explanation: The coal is classified on the basis of its physical and chemical composition. The proximate and ultimate analyses are the common tests which are used to find the commercial value of the coal. The proximate analysis gives characteristics of coal such as percentage of moisture, ash and volatile matter. Analysis of coal gives an indication about fusion temperature and heating value of the coal.

56. What is the use of electrostatic precipitations in steam power plant?
a) To remove the steam
b) To draw the coal powder into boiler
c) To remove the feed water
d) To remove fly ash
Answer: d
Explanation: The electrostatic precipitators are extensively used in the steam power plant for removal of fly ash from the electric utility boiler emission. Since the water inside the boiler is converted into steam, the fire for converting is fuelled by burning the coal which produces high amount of fly ash, so that the ash’ can be reused. The use of electrostatic precipitators is growing rapidly because of the new strict air code and environmental laws. An electrostatic can be designed to operate at any desired efficiency.

57. Why is ‘make-up water’ added to drum continuously?
a) To remove the impurities in tube
b) To replace the water that has been converted into steam
c) To keep the system cool externally
d) To compensate for water loss trough blow down
Answer: d
Explanation: Make-up water is added to compensate for the losses of water incurred by blow downs or leakages occurring in boiler, and also to maintain desired water level in boiler steam drum. Blow down and leakages are common since there is continuous flow of condensate from condenser to boiler.

58. What causes failure of boiler tube?
a) Heating the tubes, when desired water level is not maintained
b) Induced pressure in the water
c) Over use of boiler
d) Hardness of water
Answer: d
Explanation: Hardness of water causes failure of boiler tube. Hard water consists of calcium and magnesium salts. Hardness in water will form deposits on the tube water surfaces which will lead to overheating and failure of tubes. Thus the salts have to be removed from the water.