Which will make basic buffer?
a) 100 m L o f 0.1 M HCl + 200 mL of 0.1 M N H 4 O H
b) 100 mL of 0.1 M HCl + 100 mL of 0.1 M NaOH
c) 50 mL of 0.1 M NaOH +25 mL of 0.1 M C H 3 C O O H
d) 100 mL of 0.1 M C H 3 C O O H + 100 mL of 0.1 M NaOH.

Options

A. `100 mL of 0.1 M " HCl " +200 " mL of " 0.1 M NH_4OH`
B. 100 mL of 0.1 M HCl + 100 mL of 0.1 M NaOH
C. 50 mL of 0.1 M NaOH +25 mL of 0.1 M `CH_3COOH`
D. 100 mL of 0.1 M `CH_3COOH + 100 `mL of 0.1 M NaOH.

Answer

To determine which of the given options will create a basic buffer, we need to understand what a basic buffer is. A basic buffer solution is made up of a weak base and the salt of its conjugate strong acid.

Let's analyze each option step by step:

### Option A: 100 mL of 0.1 M HCl + 200 mL of 0.1 M NH₄OH
1. **Calculate the millimoles of HCl and NH₄OH:**
- HCl: \(100 \, \text{mL} \times 0.1 \, \text{M} = 10 \, \text{mmol}\)
- NH₄OH: \(200 \, \text{mL} \times 0.1 \, \text{M} = 20 \, \text{mmol}\)

2. **Determine the limiting reagent:**
- HCl is the limiting reagent (10 mmol) and NH₄OH is in excess (20 mmol).

3. **Reaction:**
- The reaction will be:
\[ \text{HCl} + \text{NH₄OH} \rightarrow \text{NH₄Cl} + \text{H₂O} \]
- After the reaction, we will have:
- 10 mmol of NH₄Cl (produced)
- 10 mmol of NH₄OH remaining (since 20 mmol - 10 mmol = 10 mmol)

4. **Conclusion:**
- We have a weak base (NH₄OH) and its salt (NH₄Cl), which fulfills the criteria for a basic buffer.

### Option B: 100 mL of 0.1 M HCl + 100 mL of 0.1 M NaOH
1. **Identify the components:**
- HCl is a strong acid and NaOH is a strong base.

2. **Conclusion:**
- This combination will neutralize each other and will not produce a buffer solution. It will result in a neutral solution.

### Option C: 50 mL of 0.1 M NaOH + 25 mL of 0.1 M CH₃COOH
1. **Identify the components:**
- NaOH is a strong base and CH₃COOH (acetic acid) is a weak acid.

2. **Conclusion:**
- This combination does not provide a weak base and its salt, so it will not create a basic buffer.

### Option D: 100 mL of 0.1 M CH₃COOH + 100 mL of 0.1 M NaOH
1. **Identify the components:**
- CH₃COOH is a weak acid and NaOH is a strong base.

2. **Conclusion:**
- This will also not create a basic buffer as it does not contain a weak base and its salt.

### Final Conclusion:
The only option that creates a basic buffer is **Option A**: 100 mL of 0.1 M HCl + 200 mL of 0.1 M NH₄OH.

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