Which of the following gases can be liquefied easily ?

Options

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

Explanation

To determine which gas can be liquefied easily among the given options, we need to consider the intermolecular forces present in each gas. The stronger the intermolecular forces, the easier it is to liquefy the gas.

### Step-by-Step Solution:

1. **Identify the Gases**:
Let's assume the gases provided in the options are:
- Option A: NH3 (Ammonia)
- Option B: CH4 (Methane)
- Option C: CO2 (Carbon Dioxide)
- Option D: H2 (Hydrogen)

2. **Analyze Intermolecular Forces**:
- **NH3 (Ammonia)**: Ammonia has hydrogen bonding due to the presence of a nitrogen atom bonded to hydrogen. This is a strong intermolecular force.
- **CH4 (Methane)**: Methane has weak London dispersion forces as it is a nonpolar molecule. It does not have significant intermolecular forces.
- **CO2 (Carbon Dioxide)**: Carbon dioxide is also a nonpolar molecule and primarily exhibits London dispersion forces, which are weak.
- **H2 (Hydrogen)**: Hydrogen gas is a diatomic molecule with very weak London dispersion forces.

3. **Compare the Strength of Intermolecular Forces**:
- Among the gases, NH3 has the strongest intermolecular forces due to hydrogen bonding.
- The other gases (CH4, CO2, H2) have weaker forces and would require lower pressures or lower temperatures to liquefy.

4. **Conclusion**:
Based on the analysis, NH3 (Ammonia) can be liquefied most easily due to the presence of strong hydrogen bonds.

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

---