An ‘Assertion’ and a ‘Reason’ is given below. Choose the correct answer from the…

An ‘Assertion’ and a ‘Reason’ is given below. Choose the correct answer from the following options:
Assertion A: Vinyl halides do not undergo nucleophilic substitution easily.
Reason R: Even though the intermediate carbocation is stabilized by loosely held π- electrons, the cleavage is difficult because of the strong bonding.
  1. Both A and R are correct statements but R is not the correct explanation of A.
  2. Both (A) and (R) are wrong statements.
  3. Both A and R are wrong statements and (R) is the correct explanation of A.
  4. A is a correct statement but R is a wrong statement.

Solution

CH2=CH-Cl does not undergo unimolecular nucleophilic substitution (SN1) reaction due to the formation of highly unstable cation CH2=CH⊕, which can not be delocalized by π- electrons. It does not give SN2 because π e- cloud is exposed, so, hindrance is there.

Asked in: JEE Main 2019 (12 Apr Shift 2)

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