State the composition of aqua regia. State which component is the oxidizing agent in aqua regia.

How will the action of dilute hydrochloric acid enable you to distinguish between the following?

(a) Sodium carbonate and sodium sulphite

(b) Sodium thiosulphate and sodium sulphite.

Write an equation for the reactions of hydrochloric acid on :

(a) silver nitrate solution

(b) magnesium foil

(c) caustic soda solution

(d) zinc carbonate

(e) manganese (IV) oxide

(f) copper oxide

Write the balanced equations for the reaction of dilute hydrochloric acid with each of the following:

(a) Iron

(b) Sodium hydrogen carbonate

(c) Iron (II) sulphide

(d) magnesium sulphite