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

The better reducing agent for ZnO is: 

1. C

2. CO

3. CO₂

4. ${\mathrm{CO}}_3^{2-}$

Zinc cannot be extracted from zinc oxide via CO reduction because:

(Given:  Ellingham diagram)