yg ini gimana caranya? mohon bantuannya

H+ = √ (kw / kb x Mg)
H+ = √(10^-14 / 2 x 10^-5 x 0,4
H+ = √ 0,2 x 10^-9
H+ = √ 2 x 10^-10
H+ = 10^-5 x √2

pH = - log H+
pH = - log ( 10^-5 x √2 )
pH = 5 - log √2