Consider the following statements concerning ortho and para hydrogen
1. Ortho is less stable man para.
2. Vapour pressure of ortho is more than of para
3. Magnetic moment of para is zero while in case of ortho it is twice that of a proton.
4. Conductivity of para is less than that of ortho.
Which of these statements are correct?

Options

A. 1 and 4
B. 2 and 3
C. 2 and 4
D. 3 and 4

Explanation

To determine which statements concerning ortho and para hydrogen are correct, let's analyze each statement step by step.

### Step 1: Analyze the Stability of Ortho and Para Hydrogen
- **Statement 1**: "Ortho is less stable than para."
- **Explanation**: Ortho hydrogen has parallel spins of protons, which gives it higher energy compared to para hydrogen, where the spins are anti-parallel. Higher energy means less stability.
- **Conclusion**: This statement is **correct**.

### Step 2: Compare the Vapor Pressure of Ortho and Para Hydrogen
- **Statement 2**: "Vapor pressure of ortho is more than that of para."
- **Explanation**: The vapor pressure of ortho hydrogen is indeed higher than that of para hydrogen. The ratio of vapor pressures is approximately 3:1, indicating that ortho hydrogen has a higher vapor pressure.
- **Conclusion**: This statement is **correct**.

### Step 3: Evaluate the Magnetic Moment of Ortho and Para Hydrogen
- **Statement 3**: "Magnetic moment of para is zero while in case of ortho it is twice that of a proton."
- **Explanation**: In para hydrogen, the magnetic moments of the two protons cancel each other out, resulting in a net magnetic moment of zero. In ortho hydrogen, the magnetic moment is indeed twice that of a single proton due to the parallel spins.
- **Conclusion**: This statement is **correct**.

### Step 4: Assess the Conductivity of Ortho and Para Hydrogen
- **Statement 4**: "Conductivity of para is less than that of ortho."
- **Explanation**: Para hydrogen has higher thermal conductivity than ortho hydrogen due to its nuclear spin configuration. The thermal conductivity of para hydrogen is approximately 50% higher than that of ortho hydrogen.
- **Conclusion**: This statement is **incorrect**.

### Final Evaluation
Based on the analysis:
1. Statement 1: Correct
2. Statement 2: Correct
3. Statement 3: Correct
4. Statement 4: Incorrect

Thus, the correct statements are **1, 2, and 3**.