Equivalent weight of sodium thiosulphate is equal to its molecular weight why?

Answer 1

The equivalent weight is the gram molecular weight divided by the number of electrons lost or gained by each molecule; e.g., potassium permanganate (KMnO4) in acid solution, 158.038/5 g; potassium dichromate (K2Cr2O7), 294.192/6 g; and sodium thiosulfate (Na2S2O3·5H2O), 248.1828/1 g. In case of Sodium Thiosulfate the reation proceeds as under: I2 + 2 Na2S2O3 → Na2S4O6 + 2 NaI 2 Na2S2O3 ≡ I2 ≡ Cl2 ≡ 2 e Hence Na2S2O3 ≡ 1 e Thus Molecular weight devded by 1 is the equivalent weight & hence both have same value

Answer 2

The equivalent weight of sodium thiosulfate is equal to its molecular weight because sodium thiosulfate has one equivalent of thiosulfate ion (S2O3^2-) per molecule. Since the thiosulfate ion acts as a reducing agent by donating electrons, its molecular weight is equivalent to one equivalent of the ion.