Ka and Kb represent the strength of an acid and a base.

The solubility of ionic solids in water is not same for salts. Some of the salts  (like calcium chloride) are so soluble that they are hygroscopic in nature and even absorb water vapour from atmosphere. Salts like lithium fluoride have so little solubility that they are commonly termed as insoluble.

The solubility depends on the lattice enthalpy of the salt and the solvation enthalpy of the ions in a solution.

For a salt to dissolve in a solvent the strong forces of attraction between its ions (lattice enthalpy) must be overcome by the ion-solvent interactions.

The solvation enthalpy of ions is referred to in terms of solvation  is always negative i.e. energy is released in the process of solvation.

The amount of solvation enthalpy depends on the nature of the solvent.

In case of a non-polar (covalent) solvent, solvation enthalpy is small and hence, not sufficient to overcome lattice enthalpy of the salt. Thus, the salt does not dissolve in non-polar solvent.

For a salt to be able to dissolve in a particular solvent its solvation enthalpy must be greater than its lattice enthalpy so that the latter may be overcome by former.

Each salt has its characteristic solubility which depends on temperature

For Soluble salts  Solubility is  > 0.1M

For  Slightly soluble salts Solubility is in the range of 0.01M to 0.1M Soluble

For sparingly soluble salts  Solubility  is < 0.01M

Ksp the solubility product constant or simply solubility product.

The concentrations of the two ions will be equal to the molar solubility of the barium sulphate.

Molar solubility of barium sulphate will be equal to 1.05 × 10–5 mol L–1.

A salt may give on dissociation two or more than two anions and cations carrying different charges.

zirconium phosphate have  molecular formula (Zr4+) 3(PO43–)4.

Zirconium phosphate dissociates into 3 zirconium cations of charge +4 and 4 phosphate anions of charge –3.