Question

Assertion (A): In electrolysis, the quantity of electricity needed for depositing 1 mole of silver is different from that required for 1 mole of copper.

Reason (R): The molecular weight of silver and copper are different.

Options

• If both A and R are true, and R is the correct explanation of A.

• If both A and R are true, but R is not the correct explanation of A.

• If A is true, but R is false.

• If both A and R are false.

Answer 1

If both A and R are true, but R is not the correct explanation of A.

Explanation:

The assertion is true because depositing 1 mole of monovalent silver (Ag⁺) requires 1 Faraday of charge (1 F), while 1 mole of divalent copper (Cu²⁺) requires 2 Faradays (2 F). The reason is also true because silver (107.87 g/mol) and copper (63.55 g/mol) have completely different molecular (atomic) weights. However, R is not the correct explanation for A because the difference in the required electrical charge depends entirely on the valency (charge of the ions) being discharged, not on their atomic weights.