Question

A pale green crystalline metal salt M dissolves freely in water. It gives a brown precipitate on addition of aqueous NaOH. The metal salt solution also gives a black precipitate on bubbling H2S in aqueous medium. An aqueous solution of the metal salt decolourises the pink colour of the permanganate solution. The metal in the metal salt solution is

Answer 1

Answer: Iron

Pale green salt contains a mixture of Fe2+ and Fe3+ ions

Fe3++3OH−⟶Fe(OH)3 brown ppt.

Fe2++S2−⟶FeS black ppt.

Fe2+ reduces KMnO4 discharging its pink colour.