The volume of 1 mole of a gas at NTP is 20 litres.

Options

A. The gas is ideal
B. The gas deviates from ideal behaviour
C. The compressibility factor,
D. `Zgt1`

Answer

To solve the problem, we need to analyze the given information about the volume of a gas at Normal Temperature and Pressure (NTP) and compare it to the expected volume for an ideal gas.

### Step-by-Step Solution:

1. **Understand NTP Conditions**:
- NTP (Normal Temperature and Pressure) is defined as a temperature of 0°C (273.15 K) and a pressure of 1 atm.
- Under these conditions, the volume of one mole of an ideal gas is approximately 22.4 liters.

2. **Given Volume of the Gas**:
- The problem states that the volume of 1 mole of the gas at NTP is 20 liters.

3. **Comparison with Ideal Gas Volume**:
- The expected volume for an ideal gas at NTP is 22.4 liters.
- Since the given volume (20 liters) is less than the ideal gas volume (22.4 liters), this indicates that the gas does not behave ideally.

4. **Calculate the Compressibility Factor (Z)**:
- The compressibility factor (Z) is defined as:
\[ Z = \frac{V_{\text{real}}}{V_{\text{ideal}}} \]
- Here, \( V_{\text{real}} = 20 \) liters and \( V_{\text{ideal}} = 22.4 \) liters.
- Plugging in the values:
\[ Z = \frac{20}{22.4} \approx 0.893 \]

5. **Interpret the Compressibility Factor**:
- Since \( Z < 1 \), this indicates that the gas is behaving more like a real gas than an ideal gas. Real gases typically deviate from ideal behavior, especially under certain conditions of pressure and temperature.

6. **Conclusion**:
- The gas deviates from ideal behavior, and the compressibility factor \( Z \) is less than 1.

### Final Answer:
- The gas is a real gas, and it deviates from ideal behavior. The compressibility factor \( Z \) is less than 1.