Question

In van der Waals equation of state of the gas law, the constant b is a measure of (a) intermolecular repulsions.

Answer 1

The bb in the Van der Waals equation of state signifies the volume that is effectively taken out per molecule by intermolecular repulsive interactions. You can imagine that a small bb will help the gas to liquefy, since in most ordinary liquids molecules are packed closer together than in a gas.