Heating an ore in a limited supply of air or in the absence of air at a temperature just below it's melting point is known as :

1. Smelting
2. Ore dressing
3. Calcination
4. Bessemerisation

Name the following :

(i) The property possessed by metals by which they can be beaten into sheets.

(ii) A compound added to lower the fusion temperature of electrolytic bath in the extraction of aluminium.

(iii) The ore of zinc containing its sulphide.

Aluminium powder is used in thermite welding because :

1. it is strong reducing agent
2. it is strong oxidizing agent
3. it is corrosion resistant
4. it is a good conductor of heat.

Select which is not an alloy of copper :

1. Brass
2. Bronze
3. Solder
4. Duralumin.