Question

Name the law or principle to which the following observations confirm:

When 9650 coulombs of electricity is passed through a solution of copper sulphate, 3.175 g of copper is deposited on the cathode (at. wt. of Cu = 63.5).

Answer 1

Faraday’s first law of electrolysis: The mass of a substance deposited or liberated at an electrode is directly proportional to the quantity of electricity passed through the electrolyte.

Given: Charge passed = 9650 C

Atomic mass of Cu = 63.5

Valency of Cu in CuSO₄ = 2

Equivalent mass of Cu = `63.5/2` = 31.75

Now, Mass deposited = `9650/96500 xx 31.75`

= 0.1 × 31.75

= 3.175 g