Question

The electrolytic cells, one containing acidified ferrous chloride and another acidified ferric chloride are connected in series. The ratio of iron deposited at cathodes in the two cells when electricity is passed through the cells will be

• A. 3 : 1
• B. 2 : 1
• C. 1 : 1
• D. 3 : 2

Answer 1

Answer: (D)

In $FeC{l}_2,F{e}^{+2}$ is present
& in $FeC{l}_3,F{e}^{+3}$ is present
At cathode: $-F{e}^{+2}+2e^{-}\to Fe$ ...(i)
$F{e}^{+3}+3e^{-}\to Fe$ ... (ii)
Equivalent weight of $F$ e in
(i) $=\frac{\text{ Atomic weight }}{n}=\frac{\text{ Atomic weight }}{2}$
Equivalent weight of $Fe$ in
(ii) $=\frac{\text{ Atomic weight }}{3}$
$\therefore$ Ratio of iron deposited at cathodes
$=\frac{A/2}{A/3}=3:2$