Q1. Electrolytic reduction of alumina to aluminium by Hall-Heroult process is carried out
Solution
In the extraction of Al,Al_2 O_3 is melted with cryolite[Na_3 (AlF_6)]. Cryolite improves the electrical conductivity of the alumina and lowers the m.p. of the mixture to about 950℃
In the extraction of Al,Al_2 O_3 is melted with cryolite[Na_3 (AlF_6)]. Cryolite improves the electrical conductivity of the alumina and lowers the m.p. of the mixture to about 950℃
Q2.Which one of the following is correct?
Solution
All minerals are not suitable for the extraction for the extraction of metals commercially. Thus, all ores are minerals, but all minerals are not ores
All minerals are not suitable for the extraction for the extraction of metals commercially. Thus, all ores are minerals, but all minerals are not ores
Q3. Sulphide ores of metals are usually concentrated by froth floatation process. Which one of the following sulphide ores offers an exception and is concentrated by leaching?
Solution
Ag,Au are obtained by complex formation
Ag,Au are obtained by complex formation
Q4. Alloys of which metal are light and strong and are used in the manufacture of aeroplanes?
Solution
Mg alloys are lighter.
Mg alloys are lighter.
Q5.One of the fertilizer is:
Solution
CaCN_2 is used as a fertilizer.
CaCN_2 is used as a fertilizer.
Q6. Which is used for the extraction of cadmium from cadmium sulphide?
Solution
d is found as traces in most Zn ores, and is extracted from these. Zn_((solid))+Cd_((solution))^(2+)→Zn_((solution))^(2+)+Cd_((solid));E=0.36 V
d is found as traces in most Zn ores, and is extracted from these. Zn_((solid))+Cd_((solution))^(2+)→Zn_((solution))^(2+)+Cd_((solid));E=0.36 V
Q7.Heating of carbonate ores to remove carbon is called as:
Solution
Calcination is a process in which the ore is heated strongly in the absence of air. (i) It removes the volatile impurities like CO_2,SO_2, organic matter, moisture from the ore. (ii)It removes water from the hydrated ore. (iii)It removes carbon as CO_2 from a carbonate ore. CaCO_3 □(→┴∆ ) CaO+CO_2 Lime stone
Calcination is a process in which the ore is heated strongly in the absence of air. (i) It removes the volatile impurities like CO_2,SO_2, organic matter, moisture from the ore. (ii)It removes water from the hydrated ore. (iii)It removes carbon as CO_2 from a carbonate ore. CaCO_3 □(→┴∆ ) CaO+CO_2 Lime stone
Q8.Which of the following is the heaviest metal?
Solution
Mass number of uranium is highest, i.e., U^238.
Mass number of uranium is highest, i.e., U^238.
Q9.Froth floatation process for the concentration of ores is a practical application of:
Solution
Gangue particles are wetted up by water and adsorbed.
Gangue particles are wetted up by water and adsorbed.
Q10. Blast furnace is used in the metallurgy of:
Solution
It is a fact
It is a fact
