Solids have a much stronger intermolecular force of attraction between their particles compared to liquids. This strong force holds the particles of the solid together, making it difficult for them to escape from the surface and enter the gas phase. As a result, the vapour pressure of solids is significantly lower than that of liquids.

In contrast, the particles in liquids are held together by weaker intermolecular forces, allowing them to move more freely and escape from the surface more easily. Therefore, liquids have a higher vapour pressure compared to solids.

The vapour pressure of a substance is directly related to its temperature. As the temperature increases, the kinetic energy of the particles also increases, causing them to move faster and overcome the intermolecular forces more easily. This leads to an increase in the vapour pressure of both solids and liquids. However, the vapour pressure of liquids increases at a faster rate compared to solids with increasing temperature due to the weaker intermolecular forces in liquids.

In summary, the strong intermolecular forces in solids compared to liquids result in a significantly lower vapour pressure for solids.