In the laboratory preparation, HCl gas is dried by passing through:

1. dilute nitric acid
2. concentrated sulphuric acid
3. dilute sulphuric acid
4. acidified water

The nitrate which on thermal decomposition leaves behind a residue which is yellow when hot and white when cold:

1. Lead nitrate
2. Ammonium nitrate
3. Copper nitrate.
4. Zinc nitrate

The property exhibited by concentrated sulphuric acid when it is used to prepare hydrogen chloride gas from potassium chloride:

1. Dehydrating property
2. Drying property
3. Oxidizing property
4. Non-volatile acid property

The hydrocarbon formed when sodium propanoate and soda lime are heated together:

1. Methane
2. Ethane
3. Ethene
4. Propane