How would the solubility of a sparinglysoluble salt, 2Mg (OH) change onincreasing the pH of the medium ? Explain

The solubility of a sparingly soluble salt, 2Mg(OH)2, would increase on increasing the pH of the medium. This can be explained by the concept of solubility equilibrium and the effect of pH on the dissociation of the salt.

When a sparingly soluble salt like 2Mg(OH)2 is dissolved in water, it undergoes a dissociation process where it breaks down into its constituent ions, in this case, Mg2+ and OH-. The solubility of the salt is determined by the equilibrium between the dissolved ions and the undissolved salt.

In an acidic medium, the concentration of H+ ions is high, which can react with the OH- ions produced by the dissociation of 2Mg(OH)2. This reaction forms water molecules, effectively removing the OH- ions from the solution. As a result, the equilibrium shifts towards the formation of more undissolved salt, leading to a lower solubility.

On the other hand, when the pH of the medium is increased, the concentration of H+ ions decreases. This reduces the availability of H+ ions to react with the OH- ions, allowing more OH- ions to remain in the solution. Consequently, the equilibrium shifts towards the dissociation of more 2Mg(OH)2, resulting in a higher solubility.

Therefore, increasing the pH of the medium would enhance the solubility of the sparingly soluble salt, 2Mg(OH)2, due to the decreased concentration of H+ ions and the reduced tendency for the formation of undissolved salt.