Which of the following statement is correct ?

Options

A. When `Z gt 1` , real gases are difficult to compress
B. When Z = 1 , real gases are easy to compress
C. When Z = 1 , real gases are easily compressed
D. When `Z gt1` , real gases are easier to compress

Answer

To solve the question regarding the compressibility factor (Z) and its implications for real gases, we will analyze each statement provided in the question step by step.

### Step 1: Understand the Compressibility Factor (Z)
The compressibility factor (Z) is defined as:
\[ Z = \frac{PV}{nRT} \]
Where:
- \( P \) = Pressure of the gas
- \( V \) = Volume of the gas
- \( n \) = Number of moles of the gas
- \( R \) = Universal gas constant
- \( T \) = Temperature of the gas

### Step 2: Analyze Each Statement
1. **Statement 1**: When Z is more than 1, real gases are difficult to compress.
- **Analysis**: When Z > 1, it indicates that the repulsive forces between gas molecules are significant, making it harder to compress the gas. This statement is **correct**.

2. **Statement 2**: When Z is 1, real gases are easy to compress.
- **Analysis**: When Z = 1, it suggests that the gas behaves ideally, meaning there are no significant intermolecular forces. Therefore, this statement is **incorrect**.

3. **Statement 3**: When Z is 1, real gases are easily compressed.
- **Analysis**: Similar to Statement 2, when Z = 1, there is no interaction between gas molecules, implying that compression is not facilitated. This statement is also **incorrect**.

4. **Statement 4**: When Z is more than 1, real gases are easier to compress.
- **Analysis**: This contradicts the first statement. If Z > 1 indicates that gases are difficult to compress, then this statement is **incorrect**.

### Conclusion
After analyzing all the statements, the only correct statement is:
- **When Z is more than 1, real gases are difficult to compress.**

### Final Answer
The correct statement is: **When Z is more than 1, real gases are difficult to compress.**

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