Question

How many Coulombs are required to oxidise 0.1 mole of H₂O to oxygen?

• A. 1.93 × 10⁵ C
• B. 1.93 × 10⁴ C
• C. 3.86 × 10⁴ C
• D. 9.65 × 10³ C

Hint:

The hint involves Faraday's laws of electrolysis to calculate the charge required for a given amount of substance.

Answer 1

The Correct Option is B

$H_2O \rightarrow H_2 + \frac{1}{2}O_2$

1 mole $H_2O \rightarrow$ 2 Faradays = $2 \times 96500 \, \text{C}$

0.1 mole $H_2O \rightarrow x \, \text{C}$

$x = \frac{2 \times 96500 \times 0.1}{1} = 19300 \, \text{C} = 1.93 \times 10^4 \, \text{C}$