An ideal gas is that which

Options

A. cannot be liquified
B. can be easily liquified
C. has strong inter molecular forces
D. has a larger size of molecules

Answer

To answer the question "An ideal gas is that which," we need to analyze the characteristics of an ideal gas based on the options provided.

### Step-by-Step Solution:

1. **Understanding Ideal Gas**: An ideal gas is a theoretical gas composed of many particles that are in constant random motion. It follows the gas laws perfectly under all conditions of temperature and pressure.

2. **Characteristics of Ideal Gas**:
- Ideal gases do not have intermolecular forces acting between the particles.
- The volume of the gas particles themselves is negligible compared to the volume of the container.
- Ideal gases can be described by the Ideal Gas Law: \( PV = nRT \).

3. **Analyzing the Options**:
- **Option 1: Cannot be liquefied**: This is consistent with the behavior of an ideal gas. Since there are no intermolecular forces, ideal gases do not condense into liquids under normal conditions.
- **Option 2: Can be easily liquefied**: This is incorrect. Real gases can be liquefied, but ideal gases cannot.
- **Option 3: Has strong intermolecular forces**: This is incorrect. Ideal gases are characterized by the absence of intermolecular forces.
- **Option 4: Has a larger size of molecules**: This is also incorrect. Ideal gases are considered to have negligible size.

4. **Conclusion**: Based on the analysis, the correct answer is that an ideal gas is one that "cannot be liquefied," which corresponds to **Option 1**.

### Final Answer:
An ideal gas is that which **cannot be liquefied**.