Liquation is used to purify:
1. Pb
2. Sn
3. Bi
4. All
Wolframite ore contains:
1. Zn
2. W
3. Hf
4. Au
The process in which ore is heated in limited supply of air below its melting point is known as:
1. Roasting
2. Calcination
3. Reduction
4. Distillation
Which substance is used as basic refractory material in furnace?
1. Al2O3
2. SiO2
3. CaO
4. Fe2O3
Rutile is an ore of:
1. Ti
2. Zr
3. Mn
4. V
Alloy is an example of:
1. gel
2. aerosol
3. solid sol
4. emulsion
The second most common element on the earth is:
1. silicon
2. hydrogen
3. nitrogen
4. oxygen
In the cyanide extraction process of silver from argentite ore, the oxidizing and reducing agents used for:
1. O2 and CO respectively
2. O2 and Zn dust respectively
3. HNO3 and Zn dust respectiely
4. HNO3 and CO respectively
Which of the following is leached with NaCN?
1. Ore of Al
2. Ore of Cu
3. Ore of Ag
4. Ore of Zn
Which of the following has a negative slope?
1. C CO
2. Fe Fe2O3
3. Mg MgO
4. All of the above
Percentage of silver in the alloy, German Silver is:-
1. 2.5%
2. 1.5%
3. 10%
4. 0%
Extraction of gold and silver involves leaching with CN- ion. Silver is later recovered by
(1) liquation
(2) distillation
(3) zone refining
(4) displacement with Zn
Which of the following elements is present as the impurity to the maximum extent in the
pig iron?
1. Carbon
2. Silicon
3. Phosphorus
4. Manganese
Chromium is obtained by reducing concentrated chromite ore with :
1. Red hot coke
2. Gaseous hydrogen
3. Aluminium powder
4. Carbon monoxide
Which is not correctly matched:
(1) spieglesian : Mn+Fe+C
(2) Dow's sea water process :
(3) parke's process :Ag
(4) liquation spelter(Impure Zn