The ore of Aluminium is:

1. Calamine
2. Haematite
3. Magnetite
4. Cryolite

Hydrogen chloride gas is not collected over water, as:

1. It is highly soluble in water.
2. It is less soluble in water.
3. It is lighter than air.
4. It is heavier than air.

The acid which is least volatile is:

1. Hydrochloric acid
2. Nitric acid
3. Dilute sulphuric acid
4. Concentrated sulphuric acid

The gas formed, when calcium bisulphite reacts with dilute HNO₃:

1. Sulphur trioxide
2. Hydrogen
3. Sulphur dioxide
4. Hydrogen sulphide