COMPASSLearning
RegisterLogin

JEE Main · 2021 · 16 Mar 2021 · Shift 1 · Alcohols Phenols and Ethers

WhatsApp Email
The products "A" and "B" formed in above reactions are:
  1. (A)(see structures)
    Structure A
    A
    Structure B
    B
  2. (B)(see structure)
    Structure A
    A
  3. (C)(see structures)
    Structure A
    A
    Structure B
    B
    ✓ Correct
  4. (D)(see structures)
    Structure A
    A
    Structure B
    B

Answer: (C)

Solution

Dilute phosphoric acid at 358 K protonates the hydroxyl group of 1-methylcyclohexan-1-ol and water leaves, giving a tertiary carbocation. The cation then loses a proton, and in this E1 route the proton comes from a ring carbon rather than from the methyl group, since that gives the trisubstituted endocyclic alkene in place of the disubstituted exocyclic one. The Saytzeff product is obtained, so A is 1-methylcyclohexene.
Potassium tert-butoxide acting on 1-chloro-1-methylcyclohexane is a one-step E2 elimination, and the base is bulky. Its approach to the crowded ring hydrogens is hindered, so it abstracts the exposed hydrogen of the methyl group and the Hofmann product is obtained. B is methylenecyclohexane.

JEE Main · 2021 · 16 Mar 2021 · Shift 1 · Single correct option

Practise more: all JEE Main PYQs on Alcohols Phenols and Ethers →

More JEE Main questions on Alcohols Phenols and Ethers

  1. Given below are two statements :

    Statement I: Phenol on treatment with aq. KOH under refluxing condition, followed by acidification produces -hydroxy benzladehyde as the major product and -hydroxy benzaldehyde as the minor product.

    Statement II …
    JEE Main 2026View solution →
  2. 3,3-Dimethyl-2-butanol cannot be prepared by:
    A.
    B.
    C.
    D.
    E.
    Choose the correct answer from the options given below:
    JEE Main 2026View solution →
  3. A mixed ether ( P ), when heated with excess of hot concentrated hydrogen iodide produces two different alkyl iodides which when treated with aq. NaOH give compounds (Q) and (R). Both (Q) and (R) give yellow precipitate with NaOI. Identify the mixed ether (P):
    JEE Main 2026View solution →
  4. Consider the following two reactions A and B .
    (A) (see structure)
    (B) (see structure)

    Numerical value of [molar mass of molar mass of y ] is ______。
    JEE Main 2026View solution →
  5. From the following, how many compounds contain at least one secondary alcohol?
    JEE Main 2026View solution →
  6. Consider the following reaction sequence

    vapour density 47]
    Compound (y) develops characteristic colour with neutral solution.
    Identify the INCORRECT statement from the following for the above sequence.
    JEE Main 2026View solution →