A plot of Gibbs energy of a reaction mixture against the exent of the reaftion is :

Options

A. minimum at eqilibrium
B. zero at equilibrium
C. miximum at equilibrium
D. None of these

Answer

To solve the question regarding the plot of Gibbs energy of a reaction mixture against the extent of the reaction, we will follow these steps:

### Step-by-Step Solution:

1. **Understanding Gibbs Energy (G)**:
- Gibbs energy (G) is a thermodynamic potential that can be used to predict the direction of chemical reactions and the position of equilibrium.

2. **Defining Spontaneous and Non-Spontaneous Reactions**:
- A spontaneous reaction has a Gibbs energy change (ΔG) that is less than zero (ΔG < 0).
- A non-spontaneous reaction has a Gibbs energy change that is greater than zero (ΔG > 0).

3. **Graphical Representation**:
- When we plot Gibbs energy (G) against the extent of the reaction, we can visualize how G changes as the reaction proceeds from reactants to products.
- For a spontaneous reaction, the graph typically shows a downward trend until it reaches a minimum point (equilibrium) and then starts to rise again.
- For a non-spontaneous reaction, the graph starts higher and decreases to a minimum point (equilibrium) before rising again.

4. **Identifying Equilibrium**:
- At equilibrium, the Gibbs energy is at a minimum. This is because the system has reached a state where the forward and reverse reactions occur at the same rate, and there is no net change in the concentrations of reactants and products.
- At this point, ΔG = 0, which signifies that the system is at equilibrium.

5. **Conclusion**:
- Based on the understanding of Gibbs energy and its behavior in spontaneous and non-spontaneous reactions, we conclude that the plot of Gibbs energy against the extent of the reaction will show a minimum at equilibrium.

### Final Answer:
The plot of Gibbs energy of a reaction mixture against the extent of the reaction is **minimum at equilibrium**.

---