Question

When aqueous solution of sodium ethanoate is electrolysed, the volume of gases obtained at cathode at a pressure of 1.0 bar and 298 K temperature when 2.0 Faraday of electricity is passed is :

• A. 67.2 litres
• B. 68.1 litres
• C. 73.2 litres
• D. 24.43 litres

Answer 1

The correct option is D 24.43 litres

When the aqueous solution of sodium ethanoate is electrolysed, the following reactions will take place:

Anode Reaction: $2C{H}_{3}COONa\to C{H}_3-C{H}_3+2C{O}_2\left(g\right)+2N{a}^{+}$

Cathode Reaction: $2N{a}^{+}+2e^{-}+2H_{2}O\to 2NaOH+H_2\left(g\right)$

$n_f$ for $H_2=2$

Equivalent weight of $H_2=\frac{M_{H_2}}{n_f}$

Moles of $H_2$ liberated at cathode$=\frac{q}{F}\times \frac{1}{n_f}=2\times \frac{1}{2}=1mole$

Volume of $H_2$ liberated$=\frac{nRT}{P}=\frac{1\times 0.082\times 298}{1}=24.43litres$