Question

Change in oxidation state of sulphur during oxidation of thiosulphate ion in neutral/alkaline solution by KMnO$_4$ is:

• A. from +2 to +6
• B. from −2 to +2
• C. from +2 to +3
• D. from +4 to +6

Hint:

Identify oxidation states of S in reactants and products; difference gives change in oxidation number.

Answer 1

The Correct Option is A

S in S$_2$O$_3^{2-}$ has oxidation state +2; after oxidation by KMnO$_4$, it forms SO$_4^{2-}$ (oxidation state +6). Hence change is +2 → +6.