Phenolphthalein can be prepared by reaction of phenol and

Options

A. phthalic anhydride
B. phathalic acid
C. terephthalic acid
D. all of these

Answer

To prepare phenolphthalein, we need to understand the reaction involved. Here’s a step-by-step solution to the question:

### Step-by-Step Solution:

1. **Identify the Reactants**:
- We need to prepare phenolphthalein, which is an acid-base indicator. The primary reactants involved in the synthesis of phenolphthalein are phenol and phthalic anhydride.

2. **Write the Reaction**:
- The reaction can be represented as:
\[ 2 \text{C}_6\text{H}_5\text{OH} + \text{C}_8\text{H}_4\text{O}_3 \rightarrow \text{C}_{20}\text{H}_{14}\text{O}_4 + \text{H}_2\text{O} \]
- Here, \( \text{C}_6\text{H}_5\text{OH} \) represents phenol and \( \text{C}_8\text{H}_4\text{O}_3 \) represents phthalic anhydride.

3. **Mechanism of the Reaction**:
- In this reaction, two molecules of phenol react with one molecule of phthalic anhydride. The hydroxyl (-OH) groups from phenol will attack the carbonyl carbon of phthalic anhydride.
- This leads to the formation of a new compound while eliminating a water molecule.

4. **Formation of Phenolphthalein**:
- The resulting compound after the reaction is phenolphthalein, which has the structure:
\[ \text{C}_{20}\text{H}_{14}\text{O}_4 \]
- The reaction results in the formation of phenolphthalein and water.

5. **Conclusion**:
- Therefore, phenolphthalein can be prepared by the reaction of phenol and phthalic anhydride.

### Final Answer:
Phenolphthalein can be prepared by the reaction of phenol and phthalic anhydride.

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