A salt of strong acid and a weak base is dissolved in water. Its hydrolysis in solution is?(A) Unaffected on heating (B) Increased by adding a strong acid (C) suppressed by diluting(D) suppressed by adding a strong acid

When a salt of a strong acid and a weak base is dissolved in water, it undergoes hydrolysis. Hydrolysis is a chemical reaction between water molecules and the ions present in the salt. The extent of hydrolysis depends on the relative strengths of the acid and the base.

In the case of a salt of a strong acid and a weak base, the anion from the salt is the conjugate base of the strong acid, while the cation is derived from the weak base. Let's denote the salt as "AB," where A represents the cation and B represents the anion.

The hydrolysis of AB can be represented by the following equation:

AB + H2O ⇌ AOH + BH

In this hydrolysis reaction, water molecules act as either acids or bases. Water can donate a proton (H+) to the anion B, making it a weak acid (BH), or it can accept a proton from the cation A, making it a weak base (AOH).

Now, let's analyze the given options:

(A) Unaffected on heating: Heating the solution does not directly affect the hydrolysis of the salt. The reaction will still proceed as described above.

(B) Increased by adding a strong acid: Adding a strong acid to the solution would increase the concentration of H+ ions in the solution. This increase in acidity can shift the equilibrium of the hydrolysis reaction to the right, favoring the formation of more weak acid (BH). Therefore, the hydrolysis would be increased by adding a strong acid.

(C) Suppressed by diluting: Diluting the solution would decrease the concentration of both the salt and the water molecules. However, since the salt is already dissociated in water, further dilution would not significantly affect the hydrolysis reaction. Therefore, hydrolysis would not be suppressed by dilution.

(D) Suppressed by adding a strong acid: Adding a strong acid would increase the concentration of H+ ions, which can react with the weak base (AOH), favoring the backward reaction and suppressing hydrolysis. Therefore, hydrolysis would be suppressed by adding a strong acid.

Based on the analysis, the correct answer is (D) suppressed by adding a strong acid.