MHTCET 23 Apr 2025 Shift 2 Paper

Concept:A chiral carbon is one that is bonded to four different groups.Explanation:Write the chain structure of 2-chloro-3,4,5-trimethylhexane:$\mathrm{CH_3-CH(Cl)-CH(CH_3)-CH(CH_3)-CH(CH_3)-CH_3}$Here, C2 has Cl, C3, C4, and C5 each have a methyl substituent.Check each carbon for chirality:C2 is attached to H, Cl, $\mathrm{CH_3}$, and the rest of the chain — all four groups are different, so C2 is chiral.C3 is attached to H, $\mathrm{CH_3}$, the C2 side, and the C4 side. These two sides are different due to the Cl atom, so C3 is chiral.C4 is attached to H, $\mathrm{CH_3}$, the C3 side, and the C5 side. These sides are also different, so C4 is chiral.C5 is attached to H, $\mathrm{CH_3}$ (substituent), $\mathrm{CH_3}$ (the terminal carbon C6), and the C4 side. Since two groups are identical methyl groups, C5 is not chiral.Therefore, the number of chiral carbon atoms is 3.Answer:B. 3