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NEET CHEMISTRYAlcohols, Phenols and EthersMedium

Question

The major product formed in the following conversion is: [Reaction Image Missing - Context suggests Alcohol Dehydration]

A

Option 1

B

Option 2

C

Option 3

D

Option 4

Step-by-Step Solution

The dehydration of alcohols to form alkenes occurs when heated with protic acids like concentrated H2SO4H_2SO_4 or H3PO4H_3PO_4. The reaction proceeds via the following mechanism:

  1. Protonation: The alcohol oxygen accepts a proton to form an alkyloxonium ion.
  2. Carbocation Formation: Loss of a water molecule forms a carbocation intermediate. This is the slow, rate-determining step. The stability order of carbocations is 3>2>13^{\circ} > 2^{\circ} > 1^{\circ}.
  3. Elimination: A proton is removed from a β\beta-carbon to form a double bond. According to Saytzeff's Rule (Zaitsev rule), the major product is the most highly substituted alkene (the one with the greater number of alkyl groups attached to the double-bonded carbon atoms).

If the starting material allows for carbocation rearrangement (e.g., hydride or methyl shift) to a more stable carbocation, the major product will be derived from the rearranged intermediate.

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 Ethersproductformedfollowingconversionreaction

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