Question

$10$ gram of a fairly concentrated solution of cupric sulphate is electrolysed using $0.01$ faraday of electrocity.
Calculate the mass (in gram) of the resulting solution
(Molecular mass of $Cu=63.5g$)

• A. $9.60\text{g}$
• B. $96.0\text{g}$
• C. $960.00\text{g}$
• D. $0.960\text{g}$

Answer 1

The correct option is A $9.60\text{g}$

Electrode process during electrolysis of aqueous $CuS{O}_4$ may be given as:
$C{u}^{2+}+2e^{-}\to Cu\left(Cathode\right)$
$2O{H}^{-}\to H_{2}O+\frac{1}{2}{O}_2+2e^{-}\left(Anode\right)$
Mass of copper deposited at cathode by 0.01 faraday of $C{u}^{2+}$ is
$0.01\times 31.75=0.3175g$

Mass of oxygen evolved by $0.01$ faraday charge
$=0.01\times 8=0.08g$
Total weight loss from solution =$0.3175+0.08=0.3975g$
Mass of reulting solution =$10-0.3975$
$=9.6025g$