Given van der Waals' constant for `NH_3, H_2, O_2 " and " CO_2 " are respectively " 4.17, 0.244, 1.36 " and " 3.59`, which one of the following gases is most easily liquefied?

Options

A. `NH_3`
B. `H_2`
C. `O_2`
D. `CO_2`

Explanation

To determine which gas among NH₃ (ammonia), H₂ (hydrogen), O₂ (oxygen), and CO₂ (carbon dioxide) is most easily liquefied, we will analyze the provided Van der Waals constants.

### Step-by-Step Solution:

1. **Understand Van der Waals Constants**:
- The Van der Waals equation for real gases is given by:
\[ \left( P + \frac{a n^2}{V^2} \right) \left( V - nb \right) = nRT \]
- Here, \(a\) (the Van der Waals constant for attraction) indicates the strength of intermolecular forces, while \(b\) (the Van der Waals constant for volume) indicates the size of the molecules.

2. **Identify the Constants**:
- For the gases given, the Van der Waals constants \(a\) are:
- NH₃: 4.17
- H₂: 0.244
- O₂: 1.36
- CO₂: 3.59

3. **Analyze the Values of \(a\)**:
- A higher value of \(a\) indicates stronger intermolecular forces, which facilitates the liquefaction of a gas.
- From the values:
- NH₃ (4.17) has the highest \(a\) value.
- CO₂ (3.59) is next.
- O₂ (1.36) follows.
- H₂ (0.244) has the lowest \(a\) value.

4. **Conclusion**:
- Since NH₃ has the highest Van der Waals constant \(a\), it indicates that it has the strongest intermolecular forces among the gases listed. Therefore, it is the gas that can be most easily liquefied.

### Final Answer:
The gas that is most easily liquefied is **NH₃ (ammonia)**.