In the metallurgy of aluminium:
1. | Al3+ is oxidised to Al(s). |
2. | The graphite anode is oxidised to carbon monoxide and carbon dioxide. |
3. | Oxidation state of oxygen change in the reaction at the anode. |
4. | The oxidation state of oxygen changes in the overall reaction involved in the process. |
Which of the following metals can be purified by electrolytic refining?
1. Cu, and Zn
2. Ge, and Si
3. Zr, and Ti
4. Zn, and Hg
The temperature at which carbon reduce FeO to Fe and produce CO is:
1. Lower than 400 oC
2. 400 oC
3. Higher than 600 oC
4. Higher than 400 oC
The correct statement among the following regarding the reaction of FeO below point A in the above diagram is:
1. Reduced by carbon monoxide only.
2. Reduced by both carbon monoxide and carbon.
3. Reduced by carbon only.
4. Not reduced by both carbon and carbon monoxide.
The correct statement for the reduction of FeO at the temperature corresponding to point D is:
1. | ∆G value for the overall reduction reaction with carbon monoxide is zero. |
2. | ∆G value for the overall reduction reaction with a mixture of 1 mol carbon, and 1 mol oxygen is positive. |
3. | ∆G value for the overall reduction reaction with a mixture of 2 mol of carbon, and 1 mol of oxygen will be positive. |
4. | ∆G value for the overall reduction reaction with carbon monoxide is negative. |
Which of the following statement is correct?
1. | Cast iron is obtained by remelting pig iron with scrap iron and coke using hot air blast. |
2. | In the extraction of silver, silver is extracted as a cationic complex. |
3. | Nickel is purified by zone refining. |
4. | Zr, and Ti are purified by the van Arkel method. |
1. (a, b)
2. (b, c)
3. (c, d)
4. (a, d)
In the extraction of aluminium by the Hall-Heroult process, purified is mixed with to:
a. | Lower the melting point of |
b. | Increase the conductivity of the molten mixture. |
c. | Reduce into |
d. | Act as a catalyst |
Choose the correct option:
1. a and b
2. b and c
3. c and d
4. a and d
From the following, the correct statements about the role of substances added in the froth flotation process are:
a. | Collectors enhance the non-wettability of the mineral particles. |
b. | Collectors enhance the wettability of gangue particles. |
c. | By using depressants in the process, two sulphide ores can be separated. |
d. | Froth stabilisers decrease the wettability of gangue. |
1. a and b
2. b and c
3. c and d
4. a and c
In the froth flotation process, how can zinc sulphide and lead sulphide be separated?
a. Using collectors.
b. Adjusting the proportion of oil to water.
c. Using depressants.
d. Using froth stabilizers.
Choose the correct option:
1. (a, b)
2. (b, c)
3. (c, d)
4. (a, d)
The common impurities present in bauxite are:
a.
b.
c.
d.
Choose the correct option:
1. a and b
2. b and c
3. c and d
4. a and d