Electrochemistry Mock Test – Class 12 Chemistry

1. The table gives possible changes during operation of a Daniell cell. Select the consistent row.

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

3. The anodic half-reaction in aqueous electrolysis with an inert electrode may be written as:

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

5. A steel spoon is electroplated with silver using a soluble silver anode. The correct arrangement is:

6. Identical clean iron nails are kept under the following conditions for the same time.

Which order of expected rusting from greatest to least is most reasonable?

7. Assertion: The overall cell reaction must be balanced before the Nernst equation is applied.
Reason: The balanced coefficients determine both the reaction-quotient powers and the electron number .

8. Match each salt-bridge feature in Column I with its consequence in Column II.

9. Assertion: Standard electrode potentials alone may not predict the observed electrolysis product correctly.
Reason: Concentration, electrode material, and overvoltage can alter the relative ease of competing electrode processes.

10. Select the row that correctly compares a spontaneously operating galvanic cell with an electrolytic cell.

11. When the complete Daniell-cell reaction is reversed while the physical state of the system is unchanged:

12. Using and , the Faraday constant is approximately:

13. The balanced anodic half-reaction for molten sodium chloride is:

14. A porous separator or electrolyte region is used in both galvanic and electrolytic devices mainly to:

15. A notation is written as . The most appropriate repair is to:

16. A silver-plating cell deposits of silver in with a current efficiency of . Given and , the current supplied is approximately:

17. The concentration-based Nernst relation at for is completed by:

18. Two weak-electrolyte solutions are compared at the same temperature.

Which conclusion is correct?

19. Use the arrangement described below. A zinc strip is immersed in , and a copper strip is immersed in . The zinc half-cell acts as the anode. The suitable notation is:

20. Two electrochemical reactions are added to form an overall reaction. Reaction P transfers of electrons and has , while Reaction Q transfers of electrons and has . If the combined reaction transfers of electrons, its standard potential is:

21. Selective discharge during electrolysis refers to:

22. The conventional order used in writing a galvanic-cell notation is:

23. The slope of a versus graph for a strong electrolyte is:

24. Rust is commonly represented approximately as ______.

25. 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:

26. A concentrated aqueous solution and a very dilute aqueous solution are electrolysed using inert electrodes. The most reasonable anodic comparison is:

27. For a strong electrolyte, and in a consistent set of concentration units. The molar conductivity at is:

28. The cathodic process in a Daniell cell is represented by:

29. Two dilution data sets for a weak acid give at and at . Which conclusion follows?

30. A balanced cell reaction is multiplied throughout by . Consider the following statements.
Statement I: The stoichiometric electron number in the written reaction becomes three times larger.
Statement II: The standard cell potential becomes three times larger.
Statement III: The standard cell potential remains unchanged.

31. Select the row that consistently describes electrolysis of aqueous with inert electrodes.

32. The values


and

are used to calculate . The result is:

33. A clean metal surface remains in dry air but begins corroding rapidly after a conducting moisture film forms. The moisture film mainly:

34. A statement says that the salt bridge carries electrons from the anode solution to the cathode solution. This description is unsuitable because:

35. A notation is written as . The reaction corresponding to the cell as written is:

36. The same solution at the same temperature is measured in four cells. Select the row with the correct relative conductance.

37. A blue solution is electrolysed for some time using pure copper electrodes. The cathode gains mass, the anode loses mass, and the blue colour changes very little. The best explanation is:

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

39. A current of is passed through molten for . Given and , the mass of aluminium produced is:

40. A zinc concentration cell at contains concentrations of and . The correct direction and emf are approximately:

41. 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:

42. Assertion: Platinum is used in a standard hydrogen electrode even though it does not appear in the net hydrogen half-reaction.
Reason: The system needs an inert electronic conductor and catalytic surface for electron exchange.

43. A learner claims that electrons in a galvanic cell move from the positive cathode to the negative anode because electrons are attracted toward a negative electrode. The suitable correction is:

44. The Daniell-cell reaction transfers of electrons and has . Using , its standard Gibbs-energy change is approximately:

45. 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:

46. At , the Nernst equation written with common logarithms is:

47. A water-blank correction is required when a saturated salt solution has measured conductivity and the blank is . Omitting the correction makes the calculated solubility:

48. For two weak acids and , the following strong-electrolyte data are available:

and

The value of is:

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

50. Select the row that consistently describes a spontaneously operating galvanic cell.