The lattice energy of fluorides is generally more than that of chlorides and if the lattice energy of a salt is high, its dissolution is less.

Explanation:

The solubility of a compound depends on several factors, including the strength of the intermolecular forces, the lattice enthalpy, and the ionization energy. In the case of fluorides and chlorides, the solubility of fluorides is much less compared to the corresponding chlorides due to the high lattice enthalpy of fluorides.

High Lattice Enthalpy:

The lattice enthalpy is a measure of the energy required to break the ionic bonds in a crystalline solid. It is directly related to the strength of the ionic forces between the ions in the crystal lattice. The greater the strength of the ionic forces, the higher the lattice enthalpy.

Fluorine is a highly electronegative element, and fluorides tend to have higher lattice enthalpies compared to chlorides. This is because the smaller size and higher charge density of fluoride ions result in stronger electrostatic attractions between the ions in the crystal lattice. As a result, more energy is required to break these strong ionic bonds, making fluorides less soluble compared to chlorides.

Low Solubility:

The high lattice enthalpy of fluorides leads to their low solubility because it requires a significant amount of energy to overcome the strong ionic forces and separate the ions. As a result, fluorides tend to be less soluble in water and other solvents compared to chlorides.

Comparison to Chlorides:

In contrast, chlorides generally have lower lattice enthalpies compared to fluorides due to the larger size and lower charge density of chloride ions. This results in weaker electrostatic attractions between the ions in the crystal lattice, making chlorides more soluble compared to fluorides.

Conclusion:

In summary, the solubility of fluorides is much less compared to the corresponding chlorides due to the high lattice enthalpy of fluorides. The strong electrostatic attractions between the smaller and more highly charged fluoride ions result in a higher energy requirement to break the ionic bonds, making fluorides less soluble in solvents.