An ideal gas , obeying kinetic theory of gases cannot be liquefied, because :-

Options

A. it solidifies before becoming a liquid
B. forces acting between its molecules are negligible
C. its critical temperature is above `0 .^(@)C`
D. its molecules are relatively small in size.

Explanation

To solve the question, "An ideal gas, obeying kinetic theory of gases cannot be liquefied, because:", we will analyze the properties of an ideal gas and the conditions required for liquefaction.

### Step-by-Step Solution:

1. **Understanding Ideal Gas Behavior**:
- An ideal gas is a theoretical gas that perfectly follows the kinetic theory of gases. According to this theory, gas molecules are in constant random motion and occupy a volume that is negligible compared to the volume of the container.

2. **Kinetic Theory of Gases**:
- The kinetic theory states that gas molecules do not exert any forces on each other except during elastic collisions. This means that there are no attractive or repulsive forces acting between the molecules when they are not colliding.

3. **Liquefaction of Gases**:
- For a gas to be liquefied, it must be subjected to conditions where the molecules can come close enough together to form intermolecular forces (like van der Waals forces). These forces are essential for the molecules to attract each other and transition from a gaseous state to a liquid state.

4. **Conclusion**:
- Since an ideal gas has negligible intermolecular forces, it cannot be liquefied. The absence of attractive forces means that the gas molecules will not come together to form a liquid, even under high pressure or low temperature.

5. **Final Answer**:
- An ideal gas cannot be liquefied because the forces acting between its molecules are negligible.