Question

To neutralize completely 20 ml of 0.1 M aqueous solution of $H_{3}P{O}_3$, the volume of 0.1 M aqueous KOH solution required is:

• A. 60 ml
• B. 20 ml
• C. 40 ml
• D. 10 ml

Answer 1

The correct option is C

40 ml

$M_{eq}of{H}_{3}P{O}_3=M_{eq}ofKOH20\times 0.1\times 2=0.1\times 1\times V$
$V=40ml$
$H_{3}P{O}_3$ is diabasic, KOH is monobasic