Question

Briefly explain how the presence of charged ions in ionic solids such as NaCl(s) helps to explain why NaCl(s) is soluble in water.

Answer 1

When any 2 substance wants to miscible, or one substance wants to get soluble in another substance, then the 2 different kinds of molecules need to interact with each other.

Not only is the interaction enough, but there must also be a strong attraction of both the molecules to get soluble in each other. The attractive forces must be strong between two molecules.

For example, the table salt NaCl dissolves easily in water because the water molecule attracts the positively charged sodium ions strongly and the negatively charged chloride ions. Due to which the solubilizing property of both is more. And hence this interaction we are calling ion-dipole interaction.

The sodium cations and chloride ions need to get distributed. For that, the water molecules have to give space for the movement of the ions. During this, some of the hydrogen bonds are lost, but the energy needed will come after the interaction of water and sodium chloride takes place.

Other salts dissolve in water but not as easily as NaCl. It is because the NaCl has lower charges due to which water can easily pull the NaCl.If the salt has more charges, the more the electrostatic attraction and chances of interaction get decrease.