Which of the following salts will give highest `pH` in water?

Options

A. KCl
B. NaCl
C. `Na_(2)CO_(3)`
D. `CuSO_(4)`

Explanation

To determine which salt will give the highest pH in water, we need to analyze the hydrolysis of each salt and identify whether they produce a strong base, a weak base, or a neutral solution.

### Step-by-Step Solution:

1. **Identify the Salts**: Let's assume the salts in question are KCl, NaCl, Na2CO3, and CuSO4.

2. **Analyze Hydrolysis of Each Salt**:
- **KCl**:
- KCl dissociates into K⁺ and Cl⁻ ions in water.
- K⁺ comes from a strong base (KOH) and Cl⁻ comes from a strong acid (HCl).
- Since both are neutral, the pH of the solution remains around 7.

- **NaCl**:
- NaCl dissociates into Na⁺ and Cl⁻ ions in water.
- Similar to KCl, Na⁺ comes from a strong base (NaOH) and Cl⁻ from a strong acid (HCl).
- Therefore, the pH also remains around 7.

- **Na2CO3**:
- Na2CO3 dissociates into 2 Na⁺ and CO3²⁻ ions in water.
- Na⁺ is neutral, but CO3²⁻ is the conjugate base of a weak acid (H2CO3).
- The presence of CO3²⁻ will hydrolyze to produce OH⁻ ions, resulting in a basic solution with a pH greater than 7.

- **CuSO4**:
- CuSO4 dissociates into Cu²⁺ and SO4²⁻ ions in water.
- Cu²⁺ is the cation of a weak base (Cu(OH)2) and SO4²⁻ comes from a strong acid (H2SO4).
- The presence of the strong acid will dominate, leading to a pH less than 7.

3. **Compare the pH Values**:
- KCl: pH ≈ 7 (neutral)
- NaCl: pH ≈ 7 (neutral)
- Na2CO3: pH > 7 (basic)
- CuSO4: pH < 7 (acidic)

4. **Conclusion**: Among the salts analyzed, Na2CO3 will give the highest pH in water due to the formation of OH⁻ ions from the hydrolysis of CO3²⁻.

### Final Answer:
The salt that will give the highest pH in water is **Na2CO3**.