Thiosulphte ${S_2O_3}^{2-}$ is oxidized to ________ in presence of permanganate ion.

${SO_4}^{2-}$

The correct answer is Option (3) → ${SO_4}^{2-}$

Reaction:

In acidic medium, thiosulphate ion (S₂O₃²⁻) is oxidized by permanganate (MnO₄⁻) to sulphate ion (SO₄²⁻).

Balanced equation (acidic medium):

8 MnO₄⁻ + 3 S₂O₃²⁻ + H₂O → 8 MnO₂ + 6 SO₄²⁻ + 2 OH⁻ (or more commonly written with H⁺ in complete form)

Key point: Each sulfur in S₂O₃²⁻ (average oxidation state +2) is oxidized to +6 in SO₄²⁻.