JEE Main · 2024 · 27 Jan 2024 · Shift 2 · General Organic Chemistry

A chiral carbon is bonded to four different groups. Going through the set: the ring carbon carrying the methyl group in 2-methylcyclohexanone is bonded to four different groups and is chiral. Cyclopentane-1,3-dione is symmetric about its carbonyl carbons and has no chiral carbon. In $C{H}_{3}C{H}_{2}CH(N{O}_2)COOH$, the carbon bearing $N{O}_2$ carries an ethyl group, $N{O}_2$, $COOH$ and H — all different — so it is chiral. In $C{H}_{3}C{H}_{2}CHBrC{H}_{2}C{H}_3$, the carbon bearing Br is flanked by two identical ethyl groups, so it is not chiral. In $C{H}_{3}CH(I)C{H}_{2}N{O}_2$, the iodine-bearing carbon has four different substituents and is chiral. In $C{H}_{3}C{H}_{2}CH(OH)C{H}_{2}OH$, the carbon bearing OH has an ethyl group, OH, $C{H}_{2}OH$ and H — all different — so it is chiral. In $C{H}_{3}CH(I)CH(I)C_2{H}_5$, both iodine-bearing carbons are each attached to four different groups and are chiral.

Counting the molecules that contain at least one chiral carbon — 2-methylcyclohexanone, the nitro-acid, the iodo-nitro compound, the hydroxy-diol compound, and the diiodo compound — gives a total of 5.