Which causes the change in the value of equilibrium constant of any equilibria ?

Options

A. Adding of inert gas at constant pressure
B. Increasing the pressure
C. Adding of inert gas at constant volume
D. Decreasing the temperature

Answer

To determine what causes a change in the value of the equilibrium constant (K) for any equilibrium, we need to analyze the factors that influence it. Here is a step-by-step solution to the question:

### Step 1: Understand the Equilibrium Constant
The equilibrium constant (K) is a numerical value that expresses the ratio of the concentrations of products to reactants at equilibrium for a given reaction at a specific temperature.

**Hint:** Recall that K is defined for a specific reaction at equilibrium and is influenced by conditions like temperature.

### Step 2: Identify Factors Affecting K
The value of the equilibrium constant is primarily affected by temperature. According to the Van't Hoff equation, the equilibrium constant changes with temperature due to the enthalpy change (ΔH) of the reaction.

**Hint:** Remember that the Van't Hoff equation relates changes in K to changes in temperature and the reaction's enthalpy.

### Step 3: Analyze Each Option
1. **Addition of Inert Gas at Constant Pressure**: Adding an inert gas at constant pressure does not change the concentration of the reactants or products, and thus does not affect K.

**Hint:** Consider how the addition of an inert gas impacts the system's pressure and volume without changing the reaction's equilibrium concentrations.

2. **Increasing Pressure**: Increasing pressure affects gaseous equilibria but does not change the equilibrium constant unless the temperature changes.

**Hint:** Think about how pressure changes might shift the position of equilibrium but not the value of K.

3. **Addition of Inert Gas at Constant Volume**: Similar to the first option, adding an inert gas at constant volume does not change the concentrations of reactants or products, so K remains unchanged.

**Hint:** Reflect on how the volume remains constant and does not alter the equilibrium concentrations.

4. **Change in Temperature**: The equilibrium constant is dependent on temperature. A change in temperature will result in a change in the value of K, depending on whether the reaction is endothermic or exothermic.

**Hint:** Consider how temperature changes can affect the reaction's enthalpy and thus the equilibrium constant.

### Step 4: Conclusion
Based on the analysis of the options, the only factor that causes a change in the value of the equilibrium constant is a change in temperature. Therefore, the correct answer is:

**Answer:** Option 4 - Temperature.