$NH_{4}Cl$ is a salt of which type?

The metal salt $A$ is blue in colour. When salt $A$ is heated strongly over a burner,a substance $B$ present in it is eliminated and a white powder $C$ is left behind. When a few drops of a liquid $D$ are added to powder $C$,it becomes blue again.
$(a)$ Identify $A, B, C, D$.
$(b)$ Write the chemical equations involved.
$(c)$ Give an example of a salt which also shows the above property.

State what happens when:
$(a)$ Chlorine gas is passed through dry slaked lime.
Also write the chemical equation in each case.

The compound which is used in glass, soap, and paper industries is:

$(a)$ State in tabular form the name of the acid and base from which the following salts are formed. Also,mention the nature of the salt,whether it is acidic or basic?
$(i)$ Sodium acetate.
$(ii)$ Ammonium sulphate.

How is bleaching powder prepared? Why does bleaching powder $(i)$ smell strongly of chlorine?