Question

Assuming complete ionization, the pH of 0.1 M, HCl is 1. The molarity of $H_2SO_4$ with the same pH is

• A. 0.1
• B. 0.2
• C. 0.05
• D. 2

Answer 1

Answer: (C)

0.05

Answer 2

$pH$ of $0.1 \,HCl= 1$ $H_{2}SO^{-}_{4} {<=>} H^{+}+HSO^{-}_{4}$ $HSO^{-}_{4} {<=>} H^{+}+SO^{2-}_{4}$ $\therefore H_{2}SO_{4}$ ionises to give two $H^{+}$ ions $\therefore 0.05\,M\,H_{2}SO_{4}$ will give $0. 1 \,M\, H^{+}$ ion $\therefore$ the molarity of $H_{2}SO_{4} = 0.05$