Question

$10$g fairly concentrated solution of $CuS{O}_4$ is electrolysed using $0.01$ faraday of electricity. The mass of resulting solution is :

• A. 9.6025 g
• B. 10.6005 g
• C. 6.6025 g
• D. None of these

Answer 1

Answer: (A)

9.6025 g

Half cell reactions :

Anode: $2H_{2}O\to 4H^{+}+O_2+4e$
Cathode: $C{u}^{2+}+2e\to Cu$

(a) $\therefore$ Mass loss at anode $=$ mass of $O_2$ formed

$=\frac{E.i.t}{96500}=\frac{32\times 0.01\times 96500}{4\times 96500}=0.08g$

Also mass loss at Cathode $=$ mass of Cu formed

$=\frac{E.i.t}{96500}=\frac{63.5\times 0.01\times 96500}{2\times 96500}=0.3175g$

$\therefore$ Mass of resulting solution $=$ Initial mass $-$ mass loss as $O_2-$ mass loss as Cu
$=10-0.08-0.3175=9.6025g$