S2O3-2→H+SO4-2. Equivalent weight of S2O3-2 ( M = Molar mass)

O.S of sulphur atom in thiosulphate ion and sulphate ion is +2 and +6 respectively.n-factor = 2(6-2) = 8 ;Alternatively O.states of two sulphur atoms in thiosulphate ion are -2 and +6 whereas in sulphate ions both sulphur atoms have +6 state.Thus change in O.S is -2→+6 …change in O.S = 8 ;n - factor = 8Eq.wt =M8