Hitunglah molalitas dan fraksi mol larutan NaOH dalam air yang kadarnya 40% (Mr NaOH=40)

Dik : massa NaOH = 40 gr (Mr = 40 gr/mol), massa H2O = 60 gr (Mr = 18 gr/mol)

Dit : n NaOH & n H2O = …?, X NaOH & X H2O = …?

Jawab : n NaOH = 40/40 = 1 mol

             n H2O = 60/18 = 3,3 mol

            X NaOH (Xt) =  = 0,2

            X H2O (Xp) =1 - 0,2 = 0,8