Isomerism

JEE Main 2024 (Online) 27th January Morning ShiftMCQMedium📈 Topic in 2% papers+4−1

Ques. 1JEE Main 2024, 27 January (Morning Shift)

Highest enol content will be shown by:

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Answer

(2) [figure]

Solution

Enol content is highest when the enol form is specially stabilised — here it becomes aromatic:

[figure]

∵ the enol of (B) is 1,3,5-trihydroxybenzene (phloroglucinol), a benzene ring (6π) ⇒ almost 100 % enol

(A): enol only conjugated with one C=O ⇒ (A) much less

(C): 1,4-C=O groups not conjugated ⇒ (C) least

(D): enol conjugated but not aromatic ⇒ (D) less

Answer: (2)

Keep practising — Isomerism

Ques. 2JEE Main 2024, 27 January (Morning Shift)

3-Methylhex-2-ene on reaction with HBr in presence of peroxide forms an addition product (A). The number of possible stereoisomers for 'A' is .

Ques. 3JEE Main 2024, 27 January (Evening Shift)

Total number of compounds with Chiral carbon atoms from following is . [figure] CH3-CH2-CH(NO2)-COOH CH3-CH2-CHBr-CH2-CH3 CH3-CH(I)-CH2-NO2 CH3-CH2-CH(OH)-CH2OH CH3- I |CH-CH(I)-C2H5

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