- 冷眼旁觀Lv 78 個月前
In acidic solution, thiosulphate ions undergo decomposition according to the following equation:
2H⁺(aq) + S₂O₃²⁻(aq) → S(s) + SO₂(aq/g) + H₂O(l)
However, the rate of the above decomposition is slow. In order to minimize the effect of the decomposition on experiment result, the titration must be done immediately after the addition of sulphuric acid.