In van der Waal's equation of state of the gas law, constant 'a' and 'b' are used. The constant 'b' is a measure of

Options

A. Volume occupied by the molecules
B. Intermolecular attraction
C. Intermolecular repulsions
D. Intermolecular collisions per unit volume

Answer

To solve the question regarding the constant 'b' in van der Waals equation of state, we can break down the information step by step.

### Step 1: Understanding the Van der Waals Equation
The Van der Waals equation is given by:
\[ P + \frac{a n^2}{V^2} = \frac{nRT}{V - nB} \]
Where:
- \( P \) = pressure of the gas
- \( V \) = volume of the gas
- \( T \) = temperature of the gas
- \( n \) = number of moles of the gas
- \( R \) = universal gas constant
- \( a \) and \( b \) = Van der Waals constants specific to each gas

### Step 2: Identifying the Role of Constant 'b'
In the Van der Waals equation, the constant 'b' is associated with the volume occupied by the gas molecules. It accounts for the finite size of the gas molecules, which is not considered in the ideal gas law. In the ideal gas law, it is assumed that gas molecules do not occupy any volume, but in reality, they do.

### Step 3: Conclusion about Constant 'b'
Thus, we can conclude that the constant 'b' is a measure of the volume occupied by the gas molecules. It represents the volume excluded from the available volume for the gas due to the presence of the molecules themselves.

### Final Answer
The constant 'b' in the van der Waals equation is a measure of the volume occupied by the gas molecules.

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