Q5 / 90 · JEE Main 2023 (25 Jan Shift 1) · Chemistry

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R:

Assertion A: Acetal/Ketal is stable in basic medium.

Reason R: The high leaving tendency of alkoxide ion gives the stability to acetal/ketal in basic medium.

In the light of the above statements, choose the correct answer from the options given below:

  • Correct answer
    A
    A is true but R is false
  • B
    A is false but R is true
  • C
    Both A and R are true and R is the correct explanation of A
  • D
    Both A and R are true but R is NOT the correct explanation of A

Solution

For Assertion: The acetals are unstable in the presence of aqueous solutions of acid because they undergo hydrolysis in the presence of acidic conditions to produce the parent aldehyde or ketone or alcohols. But are stable and do not undergo hydrolysis in the presence of a base or under neutral conditions.

Hence assertion is correct.

For reason: Alkoxide ion (RO–) is not considered a good leaving group

Hence reason must be false.

So, the correct option is A

Hence, the correct answer is option: 'A'.

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