MHT CET Chemistry Question (2026) — Solution

Step-by-step solution

The structure of 2-iodo-3,4,5-trimethylhexane is CH_3-CH(I)-CH(CH_3)-CH(CH_3)-CH(CH_3)-CH_3. Let us examine each carbon atom in the principal chain for chirality by checking if it is bonded to four different groups: C_1: Bonded to three identical hydrogen atoms, hence achiral. C_2: Bonded to -H, -I, -CH_3, and -CH(CH_3)CH(CH_3)CH(CH_3)_2. All four groups are different, making C_2 a chiral center. C_3: Bonded to -H, -CH_3, -CH(I)CH_3, and -CH(CH_3)CH(CH_3)_2. All four groups are different, making C_3 a chiral center. C_4: Bonded to -H, -CH_3, -CH(CH_3)_2, and -CH(CH_3)CH(I)CH_3. All four groups are different, making C_4 a chiral center. C_5: Bonded to -H, -CH_3, -CH_3 (from C_6), and -CH(CH_3)CH(CH_3)CH(I)CH_3. Since it is bonded to two identical methyl groups, C_5 is achiral. C_6: Bonded to three identical hydrogen atoms, hence achiral. The methyl substituents on C_3, C_4, and C_5 are also bonded to three identical hydrogen atoms and are achiral. Thus, there are exactly 3 chiral carbon atoms (C_2, C_3, and C_4). Answer: 3