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NEET CHEMISTRYAlcohols, Phenols and EthersMedium

Question

In the preparation of alkene from alcohol using Al₂O₃, which is an effective factor?

A

Porosity of Al₂O₃

B

Temperature

C

Concentration

D

Surface area of Al₂O₃

Step-by-Step Solution

The dehydration of alcohols involves passing alcohol vapours over heated alumina (Al₂O₃). The reaction is highly temperature-dependent, which determines the major product formed:

  1. At Higher Temperatures (approx. 633 K): Intramolecular dehydration (elimination) dominates, leading to the formation of Alkenes .
  2. At Lower Temperatures (approx. 513–523 K): Intermolecular dehydration (substitution) dominates, leading to the formation of Ethers. Therefore, temperature is the effective factor that controls the selectivity of the reaction toward alkenes.

Exam Context & Concepts Covered

This question aligns with the NEET CHEMISTRY syllabus, specifically targeting concepts from Alcohols, Phenols and Ethers. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.

CHEMISTRYAlcohols, Phenols and Etherspreparationalkenealcoholeffectivefactor

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