The `[H^(+)]` in a solution containing `0.1 M HCOOH` and `0.1 M HOCN` [Ka for `HCOOH` and `HOCN` are `1.8 xx 10^(-4)` and `3.3 xx 10^(-4)`] respectively will be

Options

A. `7.13 xx 10^(-2) M`
B. `7.13 xx 10^(-3) M`
C. `7.13 xx 10^(-5) M`
D. `7.13 xx 10^(-6) M`

Answer

B

Explanation

`underset((0.1-x))(HCOOH)hArr underset((x+y))(H^(o+))+underset(x)(HCOOO^(o+))`
`underset((0.1-y))(HOCN)hArr underset((x+y))(H^(o+))+underset(y)(OCN^(o+))`
`K_(HCOOH)= ([H^(+)][HCOO^(-)])/([HCOOH]) = 1.8 xx 10^(-4)`
`K_(HOCN) = ([H^(+)][OCN^(-)])/([HOCN]) = 3.3 xx 10^(-4)`