COMPASSLearning
RegisterLogin

JEE Main · 2023 · 25 Jan 2023 · Shift 1 · Aldehydes Ketones and Carboxylic Acids

WhatsApp Email
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:
  1. (A)A is true but R is false✓ Correct
  2. (B)A is false but R is true
  3. (C)Both A and R are true and R is the correct explanation of A
  4. (D)Both A and R are true but R is NOT the correct explanation of A

Answer: (A)

Solution

Acetals and ketals are gem-diethers formed from carbonyl compounds, and like ordinary ethers they are untouched by base, being hydrolysed back to the carbonyl compound only under acid. The assertion that they are stable in basic medium is thus true. The reason given is false, because an alkoxide ion is strongly basic and a poor leaving group, and it is exactly this reluctance of alkoxide to leave in base that gives the stability. The assertion is correct while the reason is false.

JEE Main · 2023 · 25 Jan 2023 · Shift 1 · Single correct option

Practise more: all JEE Main PYQs on Aldehydes Ketones and Carboxylic Acids →

More JEE Main questions on Aldehydes Ketones and Carboxylic Acids

  1. An organic compound "P" of molecular formula gives positive iodoform test but negative Tollen's test. When "P" is treated with dilute acid, it produces "Q". "Q" gives positive Tollen's test and also iodoform test. The structure of …
    JEE Main 2026View solution →
  2. Match List-I with List-II.

    List-I (Reaction Name - Involving aldehydes):
    I. Etard Reaction
    II. Rosenmund Reduction
    III. Gatterman-Koch Reaction
    IV. Stephen Reaction

    List-II (Reagents):
    A. , Pd-
    B. , HCl
    C. …
    JEE Main 2026View solution →
  3. The compound A, reacts with acetophenone to form a single product via cross-Aldol condensation. The compound A on reaction with conc. NaOH forms a substituted benzyl alcohol as
    JEE Main 2026View solution →
  4. ' ' is the product which is obtained from propanenitrile and stannous chloride in the presence of hydrochloric acid followed by hydrolysis. ' y ' is the product which is obtained from the but-2-ene by the ozonolysis followed by hydrolysis. From the following, which product is …
    JEE Main 2026View solution →
  5. From the given following (A to D) cyclic structures, those which will not react with Tollen's reagent are :
    JEE Main 2026View solution →
  6. Iodoform test can differentiate between
    A. Methanol and Ethanol
    B. and
    C. Cyclohexene and cyclohexanone
    D. Diethyl ether and Pentan-3-one
    E. Anisole and acetone

    Choose the correct answer from the …
    JEE Main 2026View solution →