A translucent white waxy solid (A) on heating in an inert atmosphere is converted to its allotropic form (B). Allotrope (A) on reaction with very dilute aqueous KOH liberates a highly poisonous gas (C) having rotten fish smell. With excess of chlorine forms (D) which hydrolyses to compound (E). Identify compounds (A) to (E).

When a mixture of ammonium chloride and potassium dichromate are heated, a stable colourless gas (A) was evolved which did not support combustion but magnesium continued to burn in it. The gas (A) reacted with calcium carbide in an electric furnance forming a solid (B). The compound (B) was slowly hydrolysed by water forming an insoluble substance (C) and the solution of substance (D) which turned Nessler’s reagent brown. Identify (A) to (E) and give the reactions involved.

An orange solid A on heating gives a colourless gas B. The gas B in dry conditions is Passed Over heated Ca to give a solid C. The solid C further reacts with water to Produce gas D which forms a blue coloured compound E on reaction with copper sulphate solution. Identify A, B,C,D,E and give the sequence of reactions involved .