Question

You have two substances at the same temperature. One is a solid and one is a liquid at that temperature. Do you think the attractions between particles in the solid are weaker or stronger than the attractions between particles in the liquid?

Answer 1

The greater the inter molecular forces in a substance the greater the attraction the molecules of the substance have for other molecules.

Because the molecules in liquid A have a greater attraction for each other the molecules in liquid A will "stick" together more than the molecules in liquid B.

The more the molecules "stick" together the greater the viscosity.