What happens in the extraction of chlorine by electrolysis of brine?
1. Oxidation of ion to chlorine gas occurs.
2. Reduction of ion to chlorine gas occurs.
3. For overall reaction has negative value.
4. A displacement reaction takes place.
What does copper matte contain?
1. Sulphides of copper(I), and iron(II)
2. Sulphides of copper (II), and iron(III)
3. Sulphides of copper(II), and iron(II)
4. Sulphides of copper(I), and iron(III)
Which of the following reactions is an example of autoreduction?
In the extraction of copper from its sulphide ore, the metal is formed by the reduction of with :
1.
2.
3.
4.
Brine is electrolysed by using inert electrodes. The reaction at the anode is:
1. Cl-(aq) → \(\frac{1}{2}\)Cl2(g) + e-; \(E_{cell}^{o}\) = 1.36 V
2. 2H2O(l) → O2(g) + 4H+ + 4 e-; \(E_{cell}^{o}\) = 1.23 V
3. Na+(aq) + e- → Na(s); \(E_{cell}^{o}\) = 2.71 V
4. H+(aq) + e- → \(\frac{1}{2}\)H2(g); \(E_{cell}^{o}\) = 0.00 V
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
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
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