On adding NaOH to ammonium sulphate, a colourless gas with pungent odour is evolved, which forms a blue-coloured complex with Cu2+ ion. Identify the gas.
Why a solution of [Ni(H2O)6]2+ is green while a solution of [Ni(CN)4]2− is colourless? (At. no. of Ni = 28)
Aqueous copper sulphate solution (blue in colour) gives:
(i) a green precipitate with aqueous potassium fluoride, and
(ii) a bright green solution with aqueous potassium chloride
Explain these experimental results.