State one relevant observation for each of the following:

i) When a crystal of copper nitrate is heated in a test tube.

iii) When hydrogen sulphide gas is  passed through lead acetate solution.

Identify the anion present in each of the following compounds;

i)  A salt M on treatment with concentrated sulphuric acid produces a gas which fumes in the moist air gives dense fumes with ammonia.

ii)  A salt D on treatment with dilute sulphuric acid produces a gas which turns lime water milky but has no effect on acidified potassium dichromate solution.

iii) When barium chloride solution is added to salt solution E a white precipitate insoluble  in dilute hydrochloric acid is obtained.

Q7.  (c)  from the list of the following salts choose the salt that most appropriately fits the description given in the following:

[AgCl, MgCl₂, NaHSO₄, PbCO₃, ZnCO₃, KNO₃,Ca(NO₃)₂]

i) A deliquescent salt

ii) An insoluble chloride

iii)  On heating, this salt gives a yellow residue when hot and white when cold.

iv)On heating this salt, a brown coloured gas is evolved.

Write a balanced chemical equation for the preparation of the following salts:
Copper carbonate