Which is/are correct statement (s)?

Options

A. `CH_(3)COONH_(4)` have greater degree of hydrolysis in 0.2 M solution in comparision os 0.4 M solution.
B. Ahnions which are weaker base than `OH^(-),` do not hydrolyse
C. The `CH_(3)COO^(-),` have greater of hydrolysis in comparision of `HCOO^(-)` when their salt solution have equal conc.
D. `SO_(4)^(2-)` hydrolyses but `HSO_(4)^(-)` does not undergo hydrolysis

Answer

To determine which statements are correct regarding hydrolysis and ionic equilibrium, we will analyze each statement step by step.

### Step 1: Analyze the first statement
The first statement discusses the equilibrium constant \( K_H \) for the hydrolysis of the acetate ion \( \text{CH}_3\text{COO}^- \) and ammonium ion \( \text{NH}_4^+ \). It states that \( K_H \) is independent of concentration.

**Analysis:**
- The hydrolysis constant \( K_H \) is defined for the reaction of a weak base with water. It is indeed independent of the concentration of the solution. The degree of hydrolysis does not depend on the concentration of the salt solution.
- Therefore, this statement is **incorrect**.

### Step 2: Analyze the second statement
The second statement claims that anions weaker than \( \text{OH}^- \) do not hydrolyze.

**Analysis:**
- Anions that are weaker bases than hydroxide ions will not hydrolyze because they cannot accept protons from water to form a stronger acid. For example, the anion \( \text{Cl}^- \) derived from a strong acid does not hydrolyze.
- Thus, this statement is **correct**.

### Step 3: Analyze the third statement
The third statement compares the hydrolysis of acetate ion \( \text{CH}_3\text{COO}^- \) with that of formate ion \( \text{HCOO}^- \).

**Analysis:**
- The hydrolysis constant \( K_b \) for the acetate ion is related to the dissociation constant \( K_a \) of acetic acid. Since acetic acid has a higher \( K_a \) than formic acid, it follows that the degree of hydrolysis \( K_H \) for acetate will be greater than that for formate.
- Thus, this statement is **correct**.

### Step 4: Analyze the fourth statement
The fourth statement discusses the hydrolysis of \( \text{HSO}_4^- \) and \( \text{SO}_4^{2-} \).

**Analysis:**
- The ion \( \text{HSO}_4^- \) is a weak acid and can undergo hydrolysis, but it cannot produce a stronger acid than itself. The sulfate ion \( \text{SO}_4^{2-} \) is a very weak base and does not hydrolyze significantly.
- Therefore, this statement is **correct**.

### Conclusion:
The correct statements are:
1. The second statement (about anions weaker than \( \text{OH}^- \) not hydrolyzing) is correct.
2. The third statement (about acetate ion having greater hydrolysis than formate ion) is correct.
3. The fourth statement (about \( \text{HSO}_4^- \) and \( \text{SO}_4^{2-} \)) is correct.

### Final Answer:
- The correct statements are the second, third, and fourth statements.