A real gas deviates from perfect gas behaviour as its molecule

Options

A. have definite size
B. attract each other
C. show browriian motion
D. are not spherical

Answer

To solve the question regarding how real gases deviate from perfect gas behavior, we will analyze the characteristics of real gases compared to ideal gases (perfect gases).

### Step-by-Step Solution:

1. **Understanding the Concept of Ideal Gases**:
- Ideal gases are theoretical gases that perfectly follow the ideal gas laws under all conditions. They are assumed to have no volume and no intermolecular forces.
- In ideal gases, the molecules are considered to be point particles that do not attract or repel each other.

**Hint**: Recall the assumptions of the ideal gas law, which include no intermolecular forces and point-like particles.

2. **Characteristics of Real Gases**:
- Real gases do not perfectly follow the ideal gas laws, especially under high pressure and low temperature conditions.
- Real gas molecules have a definite size and occupy space, which means they cannot be treated as point particles.

**Hint**: Consider how real gases behave under different conditions compared to ideal gases.

3. **Intermolecular Forces**:
- In real gases, there are attractive and repulsive forces between molecules. These forces become significant at high pressures and low temperatures, leading to deviations from ideal behavior.
- In contrast, ideal gases do not exhibit these intermolecular forces.

**Hint**: Think about the impact of intermolecular forces on the behavior of gases in real-life scenarios.

4. **Brownian Motion**:
- Both real and ideal gases exhibit Brownian motion, which is the random movement of particles suspended in a fluid. This phenomenon is not a distinguishing factor between real and ideal gases.

**Hint**: Remember that Brownian motion is a characteristic of particles in a fluid, regardless of whether they are ideal or real gases.

5. **Shape of Molecules**:
- The shape of the molecules does not significantly differ between real and ideal gases. Both can be spherical or non-spherical, but this does not affect their classification as real or ideal.

**Hint**: Consider how molecular shape relates to gas behavior and whether it is a defining characteristic.

### Conclusion:
The primary reason real gases deviate from perfect gas behavior is due to the presence of attractive and repulsive forces between the molecules. Therefore, the correct answer to the question is that real gases "attract each other," which is not the case for ideal gases.

### Final Answer:
A real gas deviates from perfect gas behavior as its molecules **attract each other**.