Consider the alkenes (I) CH3CH=CHCH3, (II) (CH3)2C=CHCH3, (III) (CH3)2C=C(CH3)2 and (IV) (CH3)2C=CH2. The correct order of the number of hyperconjugative structures is

JEE Advanced levelSingle correct optionDifficulty 3 of 3g1145

Consider the alkenes (I) $CH X_{3} CH = CHCH X_{3}$ , (II) $(CH X_{3}) X_{2} C = CHCH X_{3}$ , (III) $(CH X_{3}) X_{2} C = C (CH X_{3}) X_{2}$ and (IV) $(CH X_{3}) X_{2} C = CH X_{2}$ . The correct order of the number of hyperconjugative structures is

Alpha hydrogens: I has

2 \times 3 = 6

, II has

3 + 3 + 3 = 9

, III has

4 \times 3 = 12

, IV has

2 \times 3 = 6

. Thus III (12) > II (9) > I (6) = IV (6).