The value of van der Waals constant `a` is the maximum for

Options

A. chlorine
B. nitogen
C. Hydrogen bromide
D. helium

Explanation

To determine the value of the van der Waals constant `a` and identify which gas has the maximum value, 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 particles in a gas. It accounts for the intermolecular forces that are not considered in the ideal gas law.

2. **Identify the gases given in the question:**
- The gases mentioned are Chlorine (Cl2), Hydrogen (H2), Nitrogen (N2), and Helium (He).

3. **Analyze the nature of the gases:**
- **Helium (He):** This is a noble gas and is monoatomic. It has very weak intermolecular forces due to its inert nature, leading to a low value of `a`.
- **Hydrogen (H2):** This diatomic molecule has weak intermolecular forces due to its nonpolar nature, resulting in a low value of `a`.
- **Nitrogen (N2):** Another diatomic molecule, nitrogen has slightly stronger intermolecular forces than hydrogen but is still relatively weak.
- **Chlorine (Cl2):** Chlorine is a diatomic molecule with significant intermolecular forces due to its larger size and higher electronegativity compared to the other gases listed.

4. **Compare the values of `a`:**
- Since `a` is a measure of the strength of intermolecular attractions, we can conclude that the larger the molecule and the stronger the intermolecular forces, the higher the value of `a`.
- Among the gases listed, Chlorine (Cl2) has the strongest intermolecular forces due to its larger size and the presence of polarizable electrons.

5. **Conclusion:**
- Therefore, the value of the van der Waals constant `a` is maximum for Chlorine (Cl2).

### Final Answer:
The value of van der Waals constant `a` is maximum for Chlorine (Cl2).

---