Question

The chemical equivalent of copper and zinc are $32$ and $108$ respectively. When copper and silver voltmeter are connected in series and electric current is passed through for sometimes, $1.6\,g$ of copper is deposited. Then, the mass of silver deposited will be

• A. $3.5\,g$
• B. $2.8\,g$
• C. $5.4\,g$
• D. None of these

Answer 1

Answer: (C)

$5.4\,g$

Answer 2

From Faraday's second law, if electric currents of same strength be allowed to flow in different electrolytes for the same time, then the masses of the substances liberated are directly proportional to their chemical equivalents.
$\therefore \frac{m_{2}}{m_{1}}=\frac{E_{2}}{E_{1}}$
$\Rightarrow m_{2}=\frac{E_{2}}{E_{1}} \cdot m_{1}$
Given, $E_{2}=108, E_{1}=32$,
$m_{1}=1.6\, g$
$\therefore m_{2}=\frac{108}{32} \times 1.6=5.4\, g$