MDCAT Isomerism 2026 — Structural & Stereoisomerism

Structural Isomerism

• Chain — different carbon skeleton (n-butane vs iso-butane)
• Position — same skeleton, different functional group position
• Functional — different functional groups (ethanol vs dimethyl ether)
• Metamerism — different alkyl groups on either side of functional group
• Tautomerism — dynamic equilibrium (keto-enol)

Stereoisomerism

• Geometric (cis-trans) — restricted rotation around C=C
• Optical — chiral carbon, mirror image enantiomers (R/S)