A salt of strong acid and weak base is dissolved in water. Its hydrolysis in solution is

Options

A. Unaffected on heating
B. increased by adding strong acid
C. Suppressed by diluting
D. Suppressed by adding strong acid

Answer

To solve the question regarding the hydrolysis of a salt formed from a strong acid and a weak base when dissolved in water, we can follow these steps:

### Step 1: Identify the Components
- A salt formed from a strong acid (e.g., HCl) and a weak base (e.g., NH₄OH) will dissociate in water to give its constituent ions.
- For example, the salt NH₄Cl will dissociate into NH₄⁺ and Cl⁻ ions.

### Step 2: Understand Hydrolysis
- Hydrolysis is the reaction of the ions with water. In this case, the weak base (NH₄⁺) will undergo hydrolysis.
- The hydrolysis of NH₄⁺ can be represented as:
\[ NH₄^+ + H₂O \rightleftharpoons NH₃ + H₃O^+ \]
- This reaction shows that NH₄⁺ ions react with water to produce NH₃ (ammonia) and H₃O⁺ (hydronium ion).

### Step 3: Analyze the Effect of Strong Acid
- Since the acid is strong, it will completely dissociate in solution, contributing a significant amount of H₃O⁺ ions.
- The presence of H₃O⁺ ions will shift the equilibrium of the hydrolysis reaction to the left according to Le Chatelier's principle, suppressing the hydrolysis of the weak base.

### Step 4: Conclusion
- The hydrolysis of the salt (NH₄Cl) is suppressed due to the addition of the strong acid, which increases the concentration of H₃O⁺ ions in the solution.
- Therefore, the final conclusion is that the hydrolysis of the salt is suppressed by the strong acid.

### Final Answer
The hydrolysis of a salt formed from a strong acid and a weak base in solution is suppressed by the addition of the strong acid.

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