Electrochemistry Mock Test – Class 12 Chemistry

1. A deep scratch on a metal surface may become a preferred site for corrosion because the scratch can:

2. The reduction half-reaction has the reaction quotient:

3. Dissolving , a salt, to form a saturated solution gives molar solubility . Neglecting other sources of ions, the equilibrium ion concentrations are:

4. Under standard conditions with kinetic effects neglected, metal M displaces N and P from solutions containing and . Metal Q also displaces M from a solution containing . The relation consistent with these observations is:

5. Use the arrangement described below. Electrode P is connected to the negative terminal of a direct-current source, while electrode Q is connected to the positive terminal. Both electrodes are immersed in molten . The correct interpretation is:

6. A lead battery is examined after prolonged discharge. Both electrodes carry a substantial layer of , and the electrolyte has become less dense. The battery is most reasonably described as:

7. The Daniell-cell Nernst relation at for is:

8. An electrochemical reaction is classified as a redox reaction because it involves:

9. Which method is most suitable for obtaining of a weak electrolyte such as ?

10. Pure solids and pure liquids are normally omitted from because:

11. Equal-concentration solutions of a strong electrolyte and a weak electrolyte are diluted by the same factor. Which observation is most reasonable?

12. A metal object is partly covered by a thin electrolyte film. Oxidation occurs at one location, but the cathodic reaction is experimentally blocked everywhere else. The corrosion current falls sharply because:

13. A total of of gas is collected from both electrodes during electrolysis of acidified water. The gases are measured under identical conditions and remain separate until measurement. Their individual volumes are:

14. A student calls the central carbon rod of a dry cell “the active cathode material.” The better description is that the rod:

15. Consider the following statements for an electrolyte sample under ohmic measuring conditions.
Statement I: .
Statement II: .
Statement III: Increasing necessarily increases by the same factor.

16. Two electrolytes give the following observations when diluted by the same factor.

The most reasonable classification is:

17. Both electrodes of a lead storage cell become coated with during discharge, yet they do not undergo identical half-reactions because:

18. Consider the following statements about a concentration cell containing identical metal-metal-ion electrodes.
Statement I: .
Statement II: may be non-zero when the ion activities are unequal.
Statement III: Multiplying both ion concentrations by the same factor necessarily changes .

19. A weak-electrolyte solution has conductivity at . After dilution to , its conductivity becomes . Its molar conductivity:

20. At a cathodic region on rusting iron exposed to neutral aerated water, the principal reaction is:

21. Using and , the Faraday constant is approximately:

22. Hydrogen and chlorine produced during brine electrolysis are collected separately under identical temperature and pressure. If their combined volume is , their individual volumes are:

23. For many ordinary corrosion processes, raising the temperature tends to increase the corrosion rate because it:

24. Assertion: The absolute potential of a single isolated electrode cannot be measured directly.
Reason: A voltage measurement requires a potential difference between two electrical points.

25. The cathodic half-reaction during electrolysis of molten is:

26. The graph of against for a weak electrolyte is strongly curved mainly because:

27. The first hydroxide precipitate commonly formed when meets during rusting is produced by:

28. An electrolytic cell operates at a constant potential difference of with a current of for . The electrical energy supplied is:

29. In the combination

the ionic contributions that cancel are:

30. Solid conducts electricity very poorly, whereas molten conducts. The best explanation is that:

31. Select the row that gives the usual standard conditions for a standard hydrogen electrode.

32. A graph records electrode mass against time during steady Daniell-cell operation. Line P decreases with time, while line Q increases with time. The correct assignment is:

33. A electrode initially contains . The solution is diluted to at , with other conditions unchanged. The reduction potential of the electrode:

34. The decreasing order of oxidising strength for , , , and is:

35. Which equation represents a reduction half-reaction?

36. A steady current of flows through a circuit for . The charge transferred is:

37. Use the standard reduction potentials in the table.

The strongest oxidising agent and strongest reducing agent among the listed species are respectively:

38. Consider the following statements about the non-standard Daniell cell.
Statement I: The electron number used in the Nernst equation is .
Statement II: Activities of pure and are omitted from .
Statement III: Increasing at fixed raises .

39. Before calculating the solubility of a sparingly soluble salt from the conductivity of its saturated solution, the conductivity of pure water should be subtracted because:

40. Which combination can be used to obtain from strong-electrolyte limiting conductivities?

41. Conductivity measurements for a weak electrolyte at constant temperature are listed below.

Which set of degrees of dissociation is correct, in the same order?

42. When the iron-oxidation reaction is combined with oxygen reduction in neutral water, the initial electrochemical stage can be represented by:

43. The net ionic equation for electrolysis of aqueous with inert electrodes is:

44. For saturated , the corrected conductivity is , and . Its is:

45. Device P is a dry cell connected to a light-emitting diode. Device Q contains two electrodes in an electrolyte connected to an external direct-current source that causes a new substance to form. The energy conversions in P and Q are respectively:

46. An ideal battery has a capacity of . If it supplies a constant current of , the expected operating time is:

47. A weak electrolyte has at a particular concentration. This means that approximately:

48. A copper vessel is proposed for storing . Given and , the proposal is unsuitable because:

49. Aqueous is electrolysed using inert platinum electrodes. The principal products are:

50. A salt bridge is required for a cell containing in one half-cell and in the other. The most suitable bridge electrolyte among the following is: