Question

Assuming complete ionization, the pH of $0.1MHCl$ is 1. The molarity of $H_{2}S{O}_4$ with the same pH is :

• A. 0.1
• B. 0.2
• C. 0.05
• D. 2

Answer 1

The correct option is C 0.05

$pH$ of $0.1MHCl$ is 1.
$\therefore \left[H^{+}\right]=0.1M$
The acid dissociation reaction of $H_{2}S{O}_4$ is :
$H_{2}S{O}_4\rightleftharpoons H^{+}+HS{O}_4^{-}HS{O}_4^{-}\rightleftharpoons H^{+}+S{O}_4^{2-}$
$\therefore 1H_{2}S{O}_4$ ionizes to give $2H^{+}$ ions.
$2M{H}^{+}ions=1M{H}_{2}S{O}_{4}1M{H}^{+}ions=\frac{1}{2}M{H}_{2}S{O}_{4}0.1M{H}^{+}ions=\frac{0.1}{2}M{H}_{2}S{O}_4=0.05M{H}_{2}S{O}_4$