Which of the following is not an assumption of the kinetic theory of gases?

Options

A. A gas consists of many identical particles which are in continual motion
B. Gas particles have negligible volume
C. At high pressure, gas particles are difficult to compress
D. Collisions of gas particles are perfectly elastic.

Explanation

To determine which of the following statements is not an assumption of the kinetic theory of gases, we will analyze each option based on the principles of the kinetic theory.

### Step-by-Step Solution:

1. **Understanding the Kinetic Theory of Gases**:
- The kinetic theory of gases is based on several key assumptions about the behavior of gas molecules. These include the idea that gas consists of many small particles (molecules) that are in constant random motion, that the volume of the gas molecules is negligible compared to the volume of the container, and that there are no attractive or repulsive forces between the molecules.

2. **Evaluating Each Option**:
- **Option 1**: "A gas consists of many identical particles which are in continual motion."
- This statement aligns with the kinetic theory, which states that gas molecules are in constant random motion. **(Assumption)**

- **Option 2**: "Gas particles have negligible volume."
- This statement is also correct as the kinetic theory assumes that the volume of the gas particles is negligible compared to the volume of the container. **(Assumption)**

- **Option 3**: "At high pressure, gas particles are difficult to compress."
- This statement contradicts the kinetic theory. According to the theory, gas particles can be compressed easily regardless of the pressure because there are no significant forces of attraction or repulsion between them. **(Not an Assumption)**

- **Option 4**: "Collision of gas particles are perfectly elastic."
- This statement is true as the kinetic theory assumes that collisions between gas molecules are perfectly elastic, meaning there is no loss of kinetic energy during collisions. **(Assumption)**

3. **Conclusion**:
- The statement that is not an assumption of the kinetic theory of gases is **Option 3: "At high pressure, gas particles are difficult to compress."**

### Final Answer:
**Option 3** is not an assumption of the kinetic theory of gases.

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