The salt which will not hydrolyse in aqueous solution is :

Options

A. Copper sulphate
B. Sodium sulphate
C. Potassium cyanide
D. Sodium carbonate

Explanation

To solve the question regarding which salt will not hydrolyze in aqueous solution, we can follow these steps:

### Step 1: Understand Hydrolysis of Salts
Hydrolysis of salts occurs when a salt dissolves in water and reacts with water to produce an acidic or basic solution. This typically happens with salts derived from weak acids or weak bases.

**Hint:** Remember that hydrolysis involves the reaction of the salt with water, leading to the formation of H⁺ or OH⁻ ions.

### Step 2: Identify Types of Salts
Salts can be classified based on the strength of the acids and bases from which they are formed:
- **Strong Acid + Strong Base**: Neutral salt (does not hydrolyze)
- **Weak Acid + Strong Base**: Basic salt (hydrolyzes to produce OH⁻)
- **Strong Acid + Weak Base**: Acidic salt (hydrolyzes to produce H⁺)
- **Weak Acid + Weak Base**: Amphoteric or neutral behavior (can hydrolyze)

**Hint:** Classify the salts based on the strength of their parent acid and base.

### Step 3: Analyze the Given Options
The options provided are:
1. Weak base and strong acid
2. Strong base and strong acid
3. Weak base and weak acid
4. Strong base and weak acid

**Hint:** Look for the combination that includes both a strong acid and a strong base.

### Step 4: Determine Which Salt Will Not Hydrolyze
From the classifications:
- Option 1 (Weak base + Strong acid): Will hydrolyze, producing H⁺.
- Option 2 (Strong base + Strong acid): Will not hydrolyze; remains neutral.
- Option 3 (Weak base + Weak acid): Can hydrolyze; behavior depends on the relative strengths.
- Option 4 (Strong base + Weak acid): Will hydrolyze, producing OH⁻.

**Hint:** Identify the option that consists of both strong acid and strong base, as this will not lead to hydrolysis.

### Conclusion
The salt that will not hydrolyze in aqueous solution is the one formed from a strong acid and a strong base, which is **Option 2**.

**Final Answer:** Option 2 (Strong base and strong acid) is the correct choice.