Question

Hydrogen sulphide gas is passed over acidified kmno4

Answer 1

It’ll be oxidised to elemental sulphur or sulphate anions depending on the pH of the solution. Particulate sulphur is created if the solution is acidic or neutral, whilst alkaline solutions lead to K2SO4. Manganese dioxide, water and potassium hydroxide are the other end products in each case.

2KMnO4+ 3H2S → 2MnO2 + 3S + 2KOH + 2H2O (acid or neutral solution)

8KMnO4+ 3H2S → 8MnO2 + 2K2SO4 + 2KOH + 2H2O (alkaline solution)

Using permanganate to remove H2S and other odorous organic compounds is a technique used on an industrial scale for wastewater treatment.