A white salt is readily soluble in water and gives a colourless solution with a `pH` of about `9`. The salt would be

Options

A. `NH_(4)NO_(3)`
B. `CH_(3)COONa`
C. `CH_(3)COONH_(4)`
D. `CaCO_(3)`

Answer

To determine the identity of the white salt that is readily soluble in water and gives a colorless solution with a pH of about 9, we can follow these steps:

### Step 1: Analyze the pH
The pH of the solution is 9, which indicates that the solution is basic. A pH of 9 suggests that the salt is derived from a weak acid and a strong base. This is because:
- A strong acid and a strong base would yield a neutral solution (pH around 7).
- A weak acid and a strong base would yield a basic solution (pH greater than 7).
- A weak acid and a weak base would yield a solution with a pH close to 7.

### Step 2: Identify possible salts
We need to find salts that are formed from weak acids and strong bases. Common examples include:
- Sodium acetate (from acetic acid and sodium hydroxide)
- Potassium bicarbonate (from carbonic acid and potassium hydroxide)
- Sodium carbonate (from carbonic acid and sodium hydroxide)

### Step 3: Evaluate the options
1. **NH4NO3 (Ammonium nitrate)**: This salt is formed from a weak base (NH4OH) and a strong acid (HNO3). It would not produce a basic solution, so this option is incorrect.

2. **CH3COONa (Sodium acetate)**: This salt is formed from a weak acid (acetic acid, CH3COOH) and a strong base (sodium hydroxide, NaOH). This would produce a basic solution, making this option a potential candidate.

3. **NH4OH + CH3COOH**: This combination represents a weak acid and a weak base, which would not yield a basic solution, so this option is incorrect.

4. **CaCO3 (Calcium carbonate)**: This salt is derived from a weak acid (H2CO3) and a weak base (Ca(OH)2). It would not produce a basic solution, so this option is incorrect.

### Step 4: Conclusion
The only salt that fits the criteria of being formed from a weak acid and a strong base, and that would yield a basic solution with a pH of about 9, is sodium acetate (CH3COONa).

### Final Answer:
The salt would be **Sodium Acetate (CH3COONa)**.

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