For which of the following processes, entropy change is negative?

Options

A. Evaporation of water
B. Sublimation of camphor
C. Condensation of iodine vapour
D. Melting of ice

Answer

To determine which of the given processes has a negative change in entropy (ΔS), we need to analyze the entropy changes associated with each process.

### Step-by-Step Solution:

1. **Understanding Entropy (S)**:
- Entropy is a measure of the disorder or randomness in a system. A higher entropy value indicates a greater degree of disorder.

2. **Analyzing Sublimation of Camphor**:
- Sublimation is the process where a solid turns directly into a gas without passing through the liquid phase.
- In this case, camphor (solid) transitions to camphor vapor (gas).
- Since gases have higher entropy than solids, the entropy change (ΔS) for this process is positive.

3. **Analyzing Condensation of Iodine (I2) Vapour**:
- Condensation is the process where a gas turns into a liquid.
- When I2 vapor condenses into liquid I2, the system goes from a gaseous state (higher entropy) to a liquid state (lower entropy).
- Therefore, the entropy change (ΔS) for this process is negative.

4. **Analyzing Melting of Ice**:
- Melting is the process where a solid (ice) turns into a liquid (water).
- The transition from solid to liquid increases the disorder of the system, resulting in a positive entropy change (ΔS).

5. **Conclusion**:
- Among the processes analyzed, the only one that results in a negative change in entropy is the condensation of I2 vapor.

### Final Answer:
The process for which the entropy change is negative is **Condensation of I2 vapor**.

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