Question

4.7 g of phenol \( \xrightarrow{Zn,\Delta} X \)
If the reaction goes to 60% yield of X, find the number of moles of ‘X’ formed.

Answer 1

Correct Answer: 3

Step 1: Understanding the Question:
Phenol reacts with Zinc dust on heating to form Benzene. We need to calculate the actual yield of benzene in moles given the mass of phenol and the percentage yield.
Step 2: Detailed Explanation:
- Reaction: \(C_6H_5OH + Zn \xrightarrow{\Delta} C_6H_6 + ZnO\)
- Molar mass of Phenol (\(C_6H_5OH\)) = \((6 \times 12) + 6 + 16 = 94\) g/mol.
- Initial moles of Phenol:
\[ n_{\text{phenol}} = \frac{4.7 \text{ g}}{94 \text{ g/mol}} = 0.05 \text{ mol} \]
- According to the stoichiometry (1:1), 0.05 mol of phenol should theoretically produce 0.05 mol of Benzene ('X').
- Actual yield (60%):
\[ n_{\text{benzene}} = 0.05 \times \frac{60}{100} = 0.03 \text{ mol} \]
- Expressing in the required format: \(0.03 = 3 \times 10^{-2}\).
Step 3: Final Answer:
The number of moles of 'X' formed is \(3 \times 10^{-2}\). Thus, the value is 3.