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

Options

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

Answer

D

Explanation

`HCIrarr H^(+)+CI^(-)`
`10^(-8)M`
`H_(2)OhArr H^(+)+OH^(-)`
`{:(H_(2)OhArr,H^(+)+,OH^(-)),(, 10^(-8)+a,a):}`
`K_(w)= [H^(+)][OH^(-)]`
`:. K_(w)= (10^(-8)+a)xxa`
or `10^(-14)= 10^(-8)a+a^(2)`
or `a= 0.95xx10^(-7)`
`:. [H^(+)]= 10^(-8)+ 0.95xx10^(-7)= 1.05xx10^(-7)`