Question

In electrolytic reduction of a nitroarene with 50% current efficiency, 20.50g of the compound is reduced by $2\times 96500$ of electric charge. The molar mass of the compound is:

• A. 20.50 g
• B. 10.25 g
• C. 123.00 g
• D. 61.50 g

Answer 1

The correct option is C 123.00 g

Let the molar mass be '$M$'.

$\therefore$ Moles of compound $=\frac{20.5}{M}$

Nitroarene $+60\to X-N{H}_2$

$\frac{20.5}{M}\text{moles require}=\frac{20.5\times 6}{M}\text{moles of}{e}^{-}$

$\therefore \text{Total charge require}=\frac{20.5\times 6\times 96500}{M}$

$\therefore \frac{20.5\times 6\times 96500}{M}=\frac{2\times 96500}{efficient}\times 50$ %

$M=20.5\times 3\times 2$$=123g$