The van der Waals' constant 'a' for the gases `O_(2), N_(2), NH_(3) "and " CH_(4)` are 1.36, 1.39, 4.17 and 2.253 respectively, the gas which can be most easily liquefied is :

Options

A. `O_(2)`
B. `N_(2)`
C. `NH_(3)`
D. `CH_(4)`

Explanation

To determine which gas can be most easily liquefied based on the van der Waals constant 'a', we can follow these steps:

### Step-by-Step Solution:

1. **Understand the van der Waals constant 'a':**
The van der Waals constant 'a' is a measure of the attractive forces between gas molecules. A higher value of 'a' indicates stronger intermolecular attractions, which facilitates the liquefaction of the gas.

2. **List the given values of 'a' for each gas:**
- Oxygen (O₂): 1.36
- Nitrogen (N₂): 1.39
- Ammonia (NH₃): 4.17
- Methane (CH₄): 2.253

3. **Compare the values of 'a':**
We need to identify which gas has the highest value of 'a', as this indicates the strongest intermolecular forces and thus the gas that can be most easily liquefied.
- O₂: 1.36
- N₂: 1.39
- NH₃: 4.17
- CH₄: 2.253

4. **Identify the gas with the highest 'a' value:**
From the list, we can see that ammonia (NH₃) has the highest van der Waals constant 'a' at 4.17.

5. **Conclusion:**
Since ammonia has the highest value of 'a', it can be concluded that ammonia is the gas that can be most easily liquefied.

### Final Answer:
The gas which can be most easily liquefied is **Ammonia (NH₃)**.

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