Electrometallurgy And Corrosion MCQ

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• The following is employed as sacrificial anode to provide cathodic protection to ships, pipelines and storage tanks :
  ক

  Iron

  খ

  Copper

  গ

  Nickel

  ঘ

  Magnesium
• Displacement of metal stands for
  ক

  A metal will displace from solution

  খ

  The ions of a metal more noble than itself

  গ

  Displacement increases with increased separation between metals in the series

  ঘ

  All are correct
• Match applications in Group 1 with the commonly used corrosion protection methods in Group 2.<br>
  ক

  <table class="table-style-1"> <tr> <td><strong>Group 1</strong></td> <td><strong>Group 2</strong></td> </tr> <tr> <td>P. Sea going vessel</td> <td>1. Inorganic coating</td> </tr> <tr> <td>Q. Undergrciund pipeline</td> <td>2. Sacrificial anode</td> </tr> <tr> <td>R. Electric traction tower</td> <td>3. Aluminium paint</td> </tr> <tr> <td>S. Electric poles</td> <td>4. Impressed current</td> </tr> <tr> <td></td> <td>5. Galvanising</td> </tr></table> P-2, Q-4, R-5, S-3

  খ

  P-2, Q-3, R-5, S-1

  গ

  P-1, Q-2, R-5, S-4

  ঘ

  P-4, Q-3, R-1, S-2
• AI₂O₃ + 6H⁺ = 3H₂O + 2Al, ΔG° = 897.3 kJ, where hydrogen ion concentration is unity. The reaction potential of the above reaction under standard state will be
  ক

  - 155 V

  খ

  - 1.40 V

  গ

  1.65 V

  ঘ

  1.75 V
• For oxide layer to be protective, the Pilling Bedworth ratio should be
  ক

  close to 1

  খ

  less than 0.5

  গ

  nearly 5

  ঘ

  greater than 10
• Which of the following metal does not resists the corrosion process?
  ক

  Fe

  খ

  Ni

  গ

  Cu

  ঘ

  Pb
• What is depicted in the given polarization curve?<br><img src="/images/question-image/metallurgical-engineering/electrometallurgy-and-corrosion/1684343128-M1-18-110-22.PNG" title="Electrometallurgy and Corrosion mcq question image" alt="Electrometallurgy and Corrosion mcq question image">
  ক

  Cathodic dissolution of typical active-passive transition metal

  খ

  Anodic dissolution of typical active-passive transition metal

  গ

  Anodic dissolution of a metal

  ঘ

  Cathodic dissolution of a metal
• Identify the false statement:
  ক

  Martensitic steel are less susceptible to pitting corrosion than austenitic steels

  খ

  Pitting corrosion is usually very localised

  গ

  Hydrogen embrittlement is facilitated by tensile stress

  ঘ

  Stress corrosion cracking is facilitated by tensile stress
• A pipeline buried in soil is commonly protected from corrosion by
  ক

  anodic protection

  খ

  cathodic protection

  গ

  using inhibitors

  ঘ

  using a special alloy resistant to corrosion
• Which of the following metals is highest active in the Galvanic series?
  ক

  Alclad

  খ

  Aluminium

  গ

  Galvanized steel

  ঘ

  Zinc
• The thickness of oxide film is 'y' at a time 't' If K₁, K₂ and K₃ are the temperature dependent constants, the parabolic law of oxidation is given by
  ক

  y² = 2K₁t + K₂

  খ

  y = K₁log(K₂t + K₃)

  গ

  y = K₁f + K₂

  ঘ

  y = K₁t³ + K₂
• The passive film in stainless steel forms above the
  ক

  Primary passive potential

  খ

  Breakdown potential

  গ

  Trans-passive potential

  ঘ

  Pitting potential
• Logarithmic rate law
  ক

  Observed with thin highly protective oxide films at low temperature

  খ

  W = E log (Ft + G)

  গ

  Both A and B

  ঘ

  None of these
• Two electrolytic cells with CuSO₄ and AgNO₃ solutions are connected in series to a power source. If after 10 minutes the weight of copper (atomic weight 63.5) deposited in the first cell is 63.5 gms, the corrosponding weight of silver (atomic weight 108) deposited in the second cell is . . . . . . . . gms.
  ক

  108

  খ

  54

  গ

  216

  ঘ

  81
• The cathode in an electrochemical cell always carries
  ক

  negative charge

  খ

  positive charge

  গ

  zero charge

  ঘ

  positive or negative charge depending upon the nature of the cell
• The Faraday's laws of electrolysis are related to the
  ক

  atomic number of the cation

  খ

  atomic number of the anion

  গ

  equivalent mass of the electrolyte

  ঘ

  speed of the cation
• Which metals/alloys passivates spontaneously in acid solutions containing oxidizers or dissolved oxygen?
  ক

  Copper

  খ

  titanium

  গ

  stainless steel and titanium

  ঘ

  nickel
• Match the principle given in Group I with corresponding corrosion terminology in Group II.<br>
  ক

  <table class="table-style-1"> <tr> <td><strong>Group I</strong></td> <td><strong>Group II</strong></td> </tr> <tr> <td>P. Electrode polarization</td> <td>1. Dezincification</td> </tr> <tr> <td>Q. Passivity</td> <td>2. Intergranular attack</td> </tr> <tr> <td>R. Selective leaching</td> <td>3. Over voltage</td> </tr> <tr> <td>S. Grain boundary precipitation</td> <td>4. Surface oxide film</td> </tr></table> P-3, Q-4, R-1, S-2

  খ

  P-3, Q-4, R-2, S-1

  গ

  P-4, Q-2, R-1, S-3

  ঘ

  P-2, Q-1, R-4, S-3
• When Pt and Co are electrically connected, which one gets corroded
  ক

  Pt

  খ

  Co

  গ

  None

  ঘ

  can't decide
• Physical barriers to corrosion may be applied in the form of coating and films when
  ক

  velocity can't be change

  খ

  temperature can't be change

  গ

  both A and B

  ঘ

  none of these
• Which metals shows P-B ratio greater than 2
  ক

  Fe: 2.16, W: 3.40 &amp; V: 3.18

  খ

  U: 3.05, Mo: 3.4 &amp; Cb: 2.61

  গ

  Si: 2.27, Ta: 2.33 &amp; Sb: 2.35

  ঘ

  All are correct
• From the list given below:<br>P. Cu<br>Q. Mg<br>R. Ni<br>S. Zn<br>Two metals which provide cathode protection to steel are:
  ক

  P, R

  খ

  R, S

  গ

  Q, R

  ঘ

  Q, S
• The mathematical expression of Faraday's II Law of Electrolysis
  ক

  m ∝ Q

  খ

  $$\frac{{{m_1}}}{{{m_2}}} = \frac{{{E_1}}}{{{E_2}}}$$

  গ

  both A and B

  ঘ

  none of these
• Which protection method is depicted in then given figure?<br><img src="/images/question-image/metallurgical-engineering/electrometallurgy-and-corrosion/1684343043-M1-18-130-26.PNG" title="Electrometallurgy and Corrosion mcq question image" alt="Electrometallurgy and Corrosion mcq question image">
  ক

  Impressed-current supply method

  খ

  Anodic protection

  গ

  Sacrificial anode

  ঘ

  Anodic protection and sacrificial anode
• Uniform corrosion
  ক

  A type of corrosion attack (deterioration) uniformly distributed over a metal surface

  খ

  Corrosion that proceeds at approximately the same rate over a metal surface. Also called general corrosion

  গ

  Both A and B

  ঘ

  None of these
• Which is/are the characteristics of the vapor phase inhibitor?
  ক

  It has a very high vapor pressure

  খ

  Effective in closed spaces

  গ

  Inhibit the atmospheric corrosion without being contact with the metal surface

  ঘ

  It has very high vapor pressure, inhibit atmosphere corrosion without being contact with the metal surface and very effective in closed spaces
• When two metals or alloys are electrically coupled while exposed to an electrolyte is called
  ক

  uniform corrosion

  খ

  galvanic corrosion

  গ

  crevice corrosion

  ঘ

  erosion corrosion
• Match the corrosion phenomenon with the material in which they are commonly observed.<br>
  ক

  <table class="table-style-1"> <tr> <td>P. Season cracking</td> <td>1. 70 : 30 brass</td> </tr> <tr> <td>Q. Pitting corrosion</td> <td>2. GI water line fitted with a brass tap</td> </tr> <tr> <td>R. Galvanic corrosion</td> <td>3. Duralumin</td> </tr> <tr> <td>S. Caustic embrittlernent</td> <td>4. Boiler steel</td> </tr></table> P-1, Q-2, R-3, S-4

  খ

  P-4, Q-3, R-2, S-1

  গ

  P-1, Q-2, R-4, S-3

  ঘ

  P-3, Q-4, R-1, S-2
• The elements get oxidised with logarithmic law
  ক

  Cu, Fe, Zn

  খ

  Ni, Pb, Al

  গ

  Cr, Mn, Ti

  ঘ

  All are correct
• Chemical formula of Rust is,
  ক

  Fe₂O₃

  খ

  Fe₂O₃.XH₂O

  গ

  Fe₃O₄

  ঘ

  FeO