Q. No.
Al can reduce MgO under the following conditions:
1. Above 500 °C, Al can reduce MgO
2. Below 500 °C, Al can reduce MgO
3. Below 1350 °C, Al can reduce MgO
4. Above 1350 °C, Al can reduce MgO
The thermodynamic property useful for selecting the reducing agent is:
1. Gibbs free energy change .
2. Internal energy change.
3. Specific heat capacity.
4. None of the above.
Consider the Ellingham diagram given below.
The Y-axis, and X-axis in the graph are respectively:
1. Gibbs energy(\(\Delta G_{r}^{o} \)), and Pressure
2. Gibbs energy (\(\Delta G_{r}^{o} \)), and temperature
3. Enthalpy(\(\Delta H_{r}^{o} \)), and temperature
4. Temperature, and Gibbs energy (\(\Delta H_{r}^{o} \))
Consider the following graph.
At 1400 oC, the \(\Delta G_{r}^{o}\) the value for the reaction
2FeO + 2C → 2Fe + CO is
1. -116 kJ mol-1
2. -106 kJ mol-1
3. 100 kJ mol-1
4. -100 kJ mol-1
Zinc cannot be extracted from zinc oxide via CO reduction because:
(Given: Ellingham diagram)
| 1. | \(\Delta G_{f}^{o} \) of Zn from ZnO is lower than that of CO2 from CO |
| 2. | \(\Delta G_{f}^{o} \) of ZnO from Zn is lower than that of CO2 from CO |
| 3. | ZnO is less stable than CO |
| 4. | ZnO is more stable than CO |
| Assertion (A): | Hydrometallurgy involves dissolving the ore in a suitable reagent followed by precipitation by a more electropositive metal. |
| Reason (R): | Copper is extracted by hydrometallurgy. |
| 1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
| 3. | (A) is true but (R) is false. |
| 4. | (A) is false but (R) is true. |
| Assertion (A): | The zone refining method is very useful for producing semiconductors. |
| Reason (R): | Semiconductors are of high purity. |
| 1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
| 3. | (A) is true but (R) is false. |
| 4. | (A) is false but (R) is true. |
| Assertion (A): | Zirconium can be purified by the van Arkel method. |
| Reason (R): | ZrI4 is volatile and decomposes at 1800 K. |
| 1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
| 3. | (A) is true but (R) is false. |
| 4. | (A) is false but (R) is true. |
| Assertion (A): | Nickel can be purified by Mond’s process. |
| Reason (R): | It is a volatile compound that decomposes at 460 K to give pure Ni. |
| 1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
| 3. | (A) is true but (R) is false. |
| 4. | (A) is false but (R) is true. |
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