0.4 grams of sodium hydroxide is dissolved in 500 ml solution. The solution is now diluted by adding 500 ml of water. pH of the resultant solution is

Nb=OH-=0.440×1000500;                    =0.840N ; V1N1=V2N2; 5000.840=1000×Nb;             Nb=OH-=10-2;           pOH=2;             pH=12; Alternate method; Final volume solution=1000 ml; ∴ OH-=0.440×10001000=10-2 M;           pOH=2 ;             pH=12;