∵HCl is a strong acid. The concentration of HCl=10−8M [H+]=[H+ ]obtained from HCl + obtained by H2O ∵HCl is strong acid. ∴[H+][HCl]=1.0×10−8 The concentration ofH+ from ionisation is equal to the [OH− ] get from water and let us consider it =x. Then, [H+]H2O=[OH−]H2O=x Total [H+]=x+1.0×10−8 ∵ We know, [H+][OH−]=10−14 Solving (x) and substituting x is Eq. (i) we get, [H+]=9.5×10−8+1.0×10−8 Total [H+]=1.05×10−7