The hydrogen ion concentration of a `10^(-8) M HCl` aqueous soultion at `298 K(K_(w)=10^(-14))` is

Options

A. `1.0xx10^(-6) M`
B. `1.0525xx10^(-7) M`
C. `9.525xx10^(-8) M`
D. `1.0xx10^(-8) M`

Answer

B

Explanation

In aqueous solution of `10^(-8) M HCl`, `[H^(+)]` is based upon the concentration of `H^(+) ion` of `10^(-8) M HCl` and concentration of `H^(+) ion` of water.
`K_(w)` of `H_(2)O=10^(-14)=[H^(+)][OH^(-)]`
or `[H^(+)]=10^(-7) M` (due to its neutral behaviour)
So, in aqueous solution of `10^(-8) M HCl`,
`[H^(+)]=[H^(+)]` of `HCl+[H^(+)]` of water
`=10^(-8)+10^(-7)=11xx10^(-8) M`
`1.10xx10^(-7) M`