The correct statement among the following is:
1. | In the decomposition of oxide into oxygen and gaseous metal, entropy increases. |
2. | Decomposition of oxide is an endothermic change. |
3. | To make ∆G° negative, the temperature should be high enough so that T∆S° > ∆H°. |
4. | All of the above. |
The chemical composition of "slag" formed during the smelting process in the extraction of copper is:
1. Cu2 + FeS
2. FeSiO3
3. CuFeS
4. Cu2S + FeO
Consider the following reactions at 1000 oC.
(I) ZnS + 1/2O2(g) \(\xrightarrow[]{\Delta }\) ZnO(g); ∆Go = -360 kJ mol-1
(II) Cs + 1/2O2(g) \(\xrightarrow[]{\Delta }\) CO(g); ∆Go = -460 kJ mol-1
Choose the correct statement about the above reactions at 1000 oC:
1. ZnO is more stable than CO
2. ZnO can be reduced to Zn by C
3. ZnO, and CO are formed at an equal rate
4. ZnO can not be reduced to Zn by C
During extraction, copper is obtained by the reduction of cupric oxide with:
1. Cu2S
2. SO2
3. FeS
4. CO
Aluminium is extracted from alumina Al2O3 by electrolysis of a molten mixture of:
1.
2.
3.
4.
The correct statement among the following is:
1. | The rate of reaction cannot be understood from the Ellingham diagram. |
2. | During the formation of metal oxide \(\Delta S\) becomes negative and \(\Delta G\) becomes positive resulting in a positive slope. |
3. | There is an abrupt change in the slope of the Ellingham line when a change in phase (s→l) or (l→g) takes place. |
4. | All of the above. |
Which metal can be purified by zone refining?
1. Ni
2. Zr
3. In
4. Fe
The method of purification that is represented by the following equation is:
\(Ti(s) \ + \ 2I_{2}(g) \ \xrightarrow[]{523 \ K} \ TiI_{4}{g}\)
\(TiI_{4}(g)\ \xrightarrow[]{1700 \ K} \ Ti(s) \ + \ 2I_{2}(g)\)
1. Cupellation
2. Poling
3. Van Arkel
4. Zone refining
The fundamental principle of froth flotation process is:
1. | Impurities and metal ore have different wetting properties. |
2. | Impurities and metal ore have different solubility. |
3. | Impurities and metal ore have different diversity. |
4. | Impurities and metal ore have different compressive powers. |
Ellingham's diagram for the formation of is a straight line in the given graph.
This is due to:
1. Increase in entropy during formation.
2. Decrease in entropy during formation.
3. Entropy remains constant during formation.
4. Can not be predicted.