Question
Given below are four compounds : (a) n-propyl chloride (b) iso-propyl chloride (c) sec-butyl chloride (d) neo-pentyl chloride Percentage of carbon in the one which exhibits optical isomerism is :
JEE Main
Chemistry
General Organic Chemistry
2026
JEE Main 2026 (21 January Shift 2)
JEE Main Chemistry Question (2026) — Solution
Options
- A. 56
- B. 40
- C. 52
- D. 46
Answer
C. 52
Step-by-step solution
Optical isomerism occurs when a compound has a chiral center (asymmetric carbon). Examining each compound: n-propyl chloride (CH3CH2CH2Cl) has no chiral center, iso-propyl chloride (CH3CHClCH3) has no chiral center, sec-butyl chloride (CH3CH2CHClCH3) has one chiral center attached to four different groups, and neo-pentyl chloride has no chiral center. Therefore, sec-butyl chloride exhibits optical isomerism. For C4H9Cl: molar mass = 4(12) + 9(1) + 35.5 = 92.5 g/mol. Carbon percentage = (48/92.5) × 100 = 51.89% ≈ 52%
Related: Chemistry — General Organic Chemistry · All PYQ Banks