Which of the following can be used as a buffer solution ?

Options

A. A solution containing NaCl and NaOH
B. A solution containing NaCl and `NH_(4)OH`
C. A solution containing sodium acetate and acetic acid
D. A solution containing ammonium acetate

Explanation

To determine which of the given options can be used as a buffer solution, we need to understand the criteria for forming a buffer. A buffer solution is typically formed by the combination of:

1. A weak acid and its conjugate base (acidic buffer).
2. A weak base and its conjugate acid (basic buffer).

Now, let's analyze each option step by step:

### Step 1: Analyze the First Option - NaCl and NaOH
- **NaOH** is a strong base.
- **NaCl** is a salt formed from a strong acid (HCl) and a strong base (NaOH).
- There is no weak acid or weak base present in this combination.

**Conclusion:** This cannot form a buffer solution.

### Step 2: Analyze the Second Option - NaCl and NH4OH
- **NH4OH** (ammonium hydroxide) is a weak base.
- **NaCl** is still a salt of a strong acid and a strong base.
- There is no conjugate acid present for NH4OH in this combination (the conjugate acid would be NH4Cl).

**Conclusion:** This cannot form a buffer solution.

### Step 3: Analyze the Third Option - Sodium Acetate and Acetic Acid
- **Acetic Acid (CH3COOH)** is a weak acid.
- **Sodium Acetate (CH3COONa)** is the salt of the conjugate base of acetic acid (CH3COO^-).
- This combination consists of a weak acid and its conjugate base.

**Conclusion:** This can form an acidic buffer solution.

### Step 4: Analyze the Fourth Option - Ammonium Acetate
- **Ammonium Acetate (CH3COONH4)** consists of the conjugate base of acetic acid (CH3COO^-) and the conjugate acid of ammonia (NH4^+).
- While it contains a weak acid (NH4^+) and a weak base (CH3COO^-), it does not fit the criteria for forming a buffer as it lacks a strong acid or strong base.

**Conclusion:** This cannot form a buffer solution.

### Final Answer
The only combination that can be used as a buffer solution is **Sodium Acetate and Acetic Acid** (Option 3).

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