At a temperature above 1073 K, coke can be used to reduce FeO to Fe. It can be best explained by:

1. Ellingham diagram.

2. Orgel diagram.

3. Tunabo-Sugano diagram.

4. Born-Haber cycle.

Subtopic:  Ellingham Diagram |
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Level 1: 80%+

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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.

Subtopic:  Ellingham Diagram |
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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 (\(\Delta H_{r}^{o} \)

Subtopic:  Ellingham Diagram |
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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.

Subtopic:  Ellingham Diagram |
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Ellingham's diagram for the formation of CO2 is a straight line in the given graph. This is due to:

1. Increase in entropy during CO2 formation.

2. Decrease in entropy during CO2 formation.

3. Entropy remains constant during CO2 formation.

4. Can not be predicted.

Subtopic:  Ellingham Diagram |
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A metal's oxide that can be reduced by Fe as a reducing agent at a temperature T1 is:

1. Zr

2. Ca

3. Mg

4. None of the above.

Subtopic:  Ellingham Diagram |
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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.

Subtopic:  Ellingham Diagram |
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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

Subtopic:  Ellingham Diagram |
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Which of the following has a negative slope?

       

1. C → CO

2. Fe → Fe2O3

3. Mg → MgO

4. All of the above

Subtopic:  Ellingham Diagram |
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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

Subtopic:  Ellingham Diagram |
 62%
Level 2: 60%+

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