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
Heating of carbonate ores to remove carbon is called as:
1. Roasting
2. Calcination
3. Smelting
4. Fluxing
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
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
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