From the substances — Ammonium sulphate, Lead carbonate, Chlorine, Copper nitrate, Iron [II] sulphate — State : A compound which on heating with NaOH produces a gas which forms dense white fumes with HCl.

State what is observed when excess of ammonia is passed through an aq. solution of lead nitrate.

Write a balanced chemical equation to illustrate the reducing nature of ammonia.

With reference to Haber’s process, write the equation and the conditions required.