Liquids are typically difficult to compress due to the close arrangement of their molecules. In a liquid, the molecules are already in close proximity to one another, leaving very little empty space between them. When pressure is applied, there’s not much room for the molecules to move closer together, which is why they resist compression.
Additionally, the intermolecular forces in liquids are strong enough to hold the molecules together tightly. These forces include hydrogen bonds, dipole-dipole interactions, and Van der Waals forces. When we apply pressure to a liquid, the strong intermolecular attractions work to maintain the distance between the molecules, making it hard for them to be compressed.
The behavior of liquids contrasts sharply with gases, which have molecules that are more spread out and can be compressed significantly when pressure is applied. This fundamental difference in molecular structure and interaction is what makes liquids resistant to compression.