High purity copper metal is obtained by:

1. Carbon reduction

2. Hydrogen reduction

3. Electrolytic reduction

4. Thermite process

Aluminothermic process is used for the extraction of metals, whose oxides are:

1. fusible

2. not easily reduced  by carbon

3. not easily reduced by hydrogen

4. strongly basic

Purest form of iron is:

1. cast iron

2. hard steel

3. stainless steel

4. wrought iron

Thomas slag is:

1. calcium silicate

2. calcium  phosphate

3. tricalcium phosphate and calcium silicate

4. calcium ammonium phosphate

Corundum is:

1. SrO₂

2. Al₂O₃

3. CaCl₂

4. Cu₂Cl₂