Question

oxidation number of Central sulphur atom in Na2s2o3 would be

Answer 1

Therefore oxidation number of central sulphur atom is +6.

To find : oxidation number of central sulphur atom in Na₂S₂O₃ (sodium thiosulfate).

solution : it is difficult to find out oxidation number of central sulphur atom without using its structure. because there are two sulphur atom and both are in different nature.

see figure, here you can see one central S is e¯ doner of another S atom.

so oxidation number of S atom (i.e., S¹) = -2

with the help of S¹ atom, we can find oxidation number of central sulphur atom.

O.N of Na = +1

O.N of O = -2

now, 2 × (O.N of Na) + 3 × (O.N of O) + O.N of S¹ + O.N of central S atom = 0

⇒2 × (+1) + 3 × (-2) + (-2) + O.N of central S atom = 0

⇒O.N of central S atom = +6

Therefore oxidation number of central sulphur atom is +6.