Question

The reaction of sodium thiosulphate with i2 in aqueous solution the equivalent weight of sodium thiosulphate is equal to

Answer 1

The equivalent weight is the gram molecular weight divided by the number of electrons lost or gained by each molecule; For sodium thiosulfate (Na2S2O3·5H2O), this is (248.17/1) g.

In case of Sodium Thiosulfate the reation proceeds as under: 
I2 + 2 Na2S2O3 → Na2S4O6 + 2 NaI 
2 Na2S2O3 ≡ I2 ≡ 2 e 
Hence for one Na2S2O3 ≡ 1 e

Thus Molecular weight divided by 1 is the equivalent weight & hence both have same value.