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 a buffer solution. A buffer solution is typically made from:

1. A weak acid and its conjugate base, or
2. A weak base and its conjugate acid.

Let's analyze the options step by step:

### Step 1: Identify the components of each option
- **Option 1:** NaCl and NaOH
- **Option 2:** NH4OH and NaCl
- **Option 3:** Sodium acetate (CH3COONa) and acetic acid (CH3COOH)
- **Option 4:** Ammonium acetate (NH4CH3COO)

### Step 2: Analyze each option
1. **NaCl and NaOH:**
- NaCl is a salt formed from a strong acid (HCl) and a strong base (NaOH).
- NaOH is a strong base.
- This combination does not include a weak acid or a weak base, so it cannot act as a buffer.

2. **NH4OH and NaCl:**
- NH4OH (ammonium hydroxide) is a weak base.
- NaCl is a salt from a strong acid and a strong base.
- For a buffer, we would need NH4Cl (the conjugate acid of NH4OH) instead of NaCl. Therefore, this combination cannot act as a buffer.

3. **Sodium acetate (CH3COONa) and acetic acid (CH3COOH):**
- Acetic acid is a weak acid.
- Sodium acetate is the conjugate base of acetic acid.
- This combination fits the criteria for a buffer solution (weak acid + conjugate base), so it can act as a buffer.

4. **Ammonium acetate (NH4CH3COO):**
- Ammonium acetate can be seen as a combination of NH4+ (which is the conjugate acid of the weak base NH4OH) and CH3COO- (which is the conjugate base of the weak acid CH3COOH).
- While this combination has both a weak acid and a weak base, it does not fit the standard buffer formulation as it is not a typical weak acid/conjugate base pair. Therefore, it is less commonly used as a buffer.

### Conclusion:
The only option that can be used as a buffer solution is **Sodium acetate (CH3COONa) and acetic acid (CH3COOH)**.

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