Chemistry Alcohols & Phenols UHS 2022
PMDC Verified Question 38 of 95
Benzene is formed when Zn reacts with which of the following?
A
Alcohol
B
Propanol
C
Butyl alcohol
D
Phenol
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: Phenol
Concept:

Zinc dust is a strong reducing agent capable of cleaving the tough carbon-oxygen bond of phenols at high temperatures.

Formula:

$$ \text{C}_6\text{H}_5\text{OH} + \text{Zn (dust)} \xrightarrow{\Delta} \text{C}_6\text{H}_6 + \text{ZnO} $$

Solution:

  • When phenol is heated with zinc dust, it undergoes reduction.


  • The zinc extracts the oxygen atom to form zinc oxide (ZnO), leaving behind a hydrogen atom that reconstitutes the aromatic ring.


  • This produces pure benzene.


Why other options are incorrect:

Aliphatic alcohols (options A, B, C) do not undergo this specific deoxygenation to form benzene; they would form completely different aliphatic products if they reacted at all under these conditions.

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