Question

Which is more soluble in water $\mathrm{NaCl}\mathrm{or}\mathrm{KCl}$?

Answer 1

1. Solubility is the ability of the compound to dissolve in solvent or in solution.
2. Solubility depends upon temperature, pressure, hydration energy, and lattice energy.
3. If the hydration energy is more compared with lattice energy then the solubility increases.
4. Hydration energy is defined as the amount of energy released when one mole of ions undergoes hydration.
5. Lattice energy is defined as the amount of energy needed to change the ionic solid into a gaseous ionic constituent unit.
6. Here in this case the lattice energy is greater than hydration energy so Potassium chloride$\left(\mathrm{KCl}\right)$ is insoluble.
7. The size of Sodium ions is smaller so they easily get hydrated and therefore the hydration energy is more compared with lattice energy.
8. So, Sodium chloride$\left(\mathrm{NaCl}\right)$ is easily soluble in water and forms a covalent bond.