Which among the following indicates change in the chemical composition due to dissociation

Options

A.
B.
C.
D.

Answer

To solve the question regarding which graph indicates a change in the chemical composition due to dissociation, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Dissociation**:
- Dissociation refers to the process where a compound breaks down into two or more simpler substances or ions. For example, a compound XY might dissociate into X and Y.

2. **Recognize the Effect on Moles**:
- When a compound dissociates, the number of moles of the products increases. For instance, if one mole of XY dissociates into two moles (X and Y), the total number of moles increases from 1 to 2.

3. **Apply the Ideal Gas Law**:
- The ideal gas equation is given by \( PV = nRT \), where:
- \( P \) = pressure
- \( V \) = volume
- \( n \) = number of moles
- \( R \) = ideal gas constant
- \( T \) = temperature
- If the number of moles \( n \) increases due to dissociation, then \( PV \) must also change to maintain the equality.

4. **Analyze the Graphs**:
- We are given four graphs to analyze. We need to identify which graph shows a change in \( PV/T \) that corresponds with an increase in the number of moles due to dissociation.
- Initially, \( PV/T \) is constant, but as dissociation occurs and the number of moles increases, \( PV/T \) should also increase.

5. **Identify the Correct Graph**:
- Look for a graph where \( PV/T \) increases initially with dissociation and then stabilizes once all reactants have dissociated. This behavior indicates a change in chemical composition due to dissociation.

6. **Conclusion**:
- Based on the analysis, the correct graph that indicates a change in chemical composition due to dissociation is **Option C**.