Question

To neutralize completely 20 mL of 0.1M aqueous solution of phosphorus acid `(H_(3)PO_(3))` the volume of `0.1M` aqueous KOH solution required is
A. `10mL`
B. `20 mL`
C. `40 mL`
D. `60 mL`

Answer 1

Correct Answer - C
`H_(3)PO_(3)` is a dibasic acid.
`H_(3)PO_(3)+2KOH rarr K_(2)HPO_(3)+2H_(2)O`
`(M_(A)V_(A))/(n_(A))=(M_(B)V_(B))/(n_(B))`
`(0.1xx20)/(1) = (0.1xxV_(B))/(2)`
`V_(B)=40 mL`