JEE Main 2025 Jan 22 Shift 1, Chemistry Q3: Stereoisomerism

The molecule pent-3-en-2-ol, ${\text{CH}}_3-\text{CH(OH)}-\text{CH}=\text{CH}-{\text{CH}}_3$, contains two independent stereogenic elements:

(i) one chiral carbon (C2) bearing $-$OH, giving R or S, and

(ii) one disubstituted C=C double bond (between C3 and C4), giving cis or trans.

Total stereoisomers $=2\times 2=4$ (R-cis, R-trans, S-cis, S-trans).