Purest form of iron is:

1. cast iron

2. hard steel

3. stainless steel

4. wrought iron

Sulphide ores are common for the metals:

1. Ag, Cu and Pb

2. Ag, Cu and Sn

3. Ag, Mg and Pb

4. Al, Cu and Pb

Heating of carbonate ores to remove carbon is called as:

1. Roasting

2. Calcination

3. Smelting

4. Fluxing

Chloride ore among the following is:

1. malachite

2. magnesite

3. magnetite

4. Karnalite

Which process is not used in purification of bauxite?

1. Hall's method

2. Baeyer's method

3. Serpek's method

4. Frankland's method

Corundum is:

1. SrO₂

2. Al₂O₃

3. CaCl₂

4. Cu₂Cl₂

Thomas slag is:

1. calcium silicate

2. calcium  phosphate

3. tricalcium phosphate and calcium silicate

4. calcium ammonium phosphate

Chalcogens are: 

1. hydrocarbons 

2. ore forming elements 

3. oxide forming elements

4. those having ability to catenate

Which element occurs freely in nature?

1. Iodine

2. Sulphur

3. Phosphorus

4. Magnesium

Silver obtained by argentiferrous lead is purified by:

1. distillation

2. froth floatation

3. cupellation

4. reacting with KCN