Which of the following salts undergoes hydrolysis ?

Options

A. `Na_2SO_4`
B. `CH_3COOK`
C. `KNO_3`
D. NaBr

Answer

To determine which of the following salts undergoes hydrolysis, we need to analyze the behavior of the cations and anions in water. Hydrolysis occurs when a salt dissociates in water and either the cation or the anion reacts with water to form an acid or a base.

### Step-by-Step Solution:

1. **Identify the salts and their components**:
Let's assume we have the following salts: NaCl, KNO3, CH3COONa, and NH4Cl. Each salt consists of a cation and an anion.

2. **Analyze the cations**:
- **Na+**: This cation comes from NaOH, which is a strong base. Therefore, it does not undergo hydrolysis.
- **K+**: This cation comes from KOH, which is also a strong base. Therefore, it does not undergo hydrolysis.
- **NH4+**: This cation comes from NH4OH, which is a weak base. It can undergo hydrolysis to form NH3 and H+.

3. **Analyze the anions**:
- **Cl-**: This anion comes from HCl, which is a strong acid. Therefore, it does not undergo hydrolysis.
- **NO3-**: This anion comes from HNO3, which is a strong acid. Therefore, it does not undergo hydrolysis.
- **CH3COO-**: This anion comes from acetic acid (CH3COOH), which is a weak acid. It can undergo hydrolysis to form CH3COOH and OH-.

4. **Determine which salts can undergo hydrolysis**:
- From the analysis, we see that:
- NH4Cl can undergo hydrolysis because NH4+ is a weak base.
- CH3COONa can undergo hydrolysis because CH3COO- is a weak acid.
- The other salts (NaCl and KNO3) do not undergo hydrolysis because they consist of strong acids and strong bases.

5. **Conclusion**:
The salts that undergo hydrolysis are NH4Cl and CH3COONa.

### Final Answer:
The salts that undergo hydrolysis are **NH4Cl and CH3COONa**.