The values of van der Waals constant 'a' for a gas is zero. What does it signify ?

Explanation

To understand the significance of the van der Waals constant 'a' being zero for a gas, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Van der Waals Equation**:
The van der Waals equation is given by:
\[
\left(P + \frac{a n^2}{V^2}\right)(V - nB) = nRT
...