Identify the salt Q from the following observation:

Salt Q is white in colour. On strong heating, it produces buff-yellow residue and liberates a reddish-brown gas. Solution of salt Q produces chalky white insoluble precipitate with an excess of ammonium hydroxide.

Give one phrase for the following statement:

The property by which certain hydrated salts, when left exposed to atmosphere, lose their water of crystallization and crumble into powder.

State one relevant observation for of the following:

Lead nitrate solution is mixed with dilute hydrochloric acid and heated.

State one relevant observation for of the following:

Anhydrous calcium chloride is exposed to air for some time.

Write a balanced equation for the preparation of the following salt: Copper sulphate from Copper carbonate.

Write a balanced chemical equation the following reaction:

Action of dilute sulphuric acid on sodium hydroxide.

Identify the salt R from the following observation:

Salt R is black in colour. On reacting with concentrated $\mathrm{HCl}$, it liberates a pungent greenish-yellow gas which turns moist starch iodide paper blue-black.