The pH of `10^(-8)` M HCl solution is

Options

A. 8
B. more than 8
C. between 6 and 7
D. slightly more than 7

Answer

C

Explanation

From `H_(2)O, [H^(+)]=1xx10^(-7)M`
From HCl, `[H^(+)]=1xx10^(-8)M`
`therefore` Total `[H^(+)]=(1xx10^(-7)+1xx10^(-8))M`
`=(1xx10^(-7)+0.1xx10^(-7))M=1.1xx10^(-7)M`
`therefore pH =-log (1.1xx10^(-7))=6.9586`