Which of the following indicators is the best indicator for the detection of end point in the titration of `CH_(3)COOH` and KOH ?

Options

A. methyl organge
B. phenolphthalein
C. methyl red
D. none of these

Answer

To determine the best indicator for the titration of acetic acid (CH₃COOH) and potassium hydroxide (KOH), we need to consider the nature of the acid and base involved in the reaction.

### Step-by-Step Solution:

1. **Identify the Acid and Base**:
- The acid is acetic acid (CH₃COOH), which is a weak acid.
- The base is potassium hydroxide (KOH), which is a strong base.

2. **Understand the Titration Reaction**:
- When a weak acid is titrated with a strong base, the equivalence point of the titration will occur in a basic medium. This is because the strong base will dominate the reaction.

3. **Determine the pH at the Equivalence Point**:
- In the titration of a weak acid with a strong base, the pH at the equivalence point will be greater than 7 (basic).

4. **Select Appropriate Indicators**:
- Indicators change color at specific pH ranges. We need to choose one that changes color around the pH of the equivalence point.
- Common indicators and their pH ranges:
- **Methyl Orange**: pH range 3.2 to 4.4 (acidic)
- **Phenolphthalein**: pH range 8.2 to 10 (basic)
- **Methyl Red**: pH range 4.8 to 6.0 (acidic)

5. **Analyze the Indicators**:
- **Methyl Orange** and **Methyl Red** are suitable for acidic solutions and will not be effective in a basic medium.
- **Phenolphthalein**, with a transition range of 8.2 to 10, is suitable for detecting the endpoint in a basic medium.

6. **Conclusion**:
- Since the titration of acetic acid with potassium hydroxide results in a basic solution at the equivalence point, the best indicator to use is **Phenolphthalein**.

### Final Answer:
The best indicator for the detection of the endpoint in the titration of CH₃COOH and KOH is **Phenolphthalein**.