Medium Practice — Set 2

Quick Recap — Stereochemistry, Reactivity & Uses

• SN2 inverts (Walden inversion); SN1 racemises; steric bulk kills SN2, carbocation stability drives SN1.
• Best leaving group: $I^->Br^->Cl^->F^-$ (weakest base leaves best).
• Haloarenes/vinyl halides are unreactive to $S_N$ (resonance + $sp^2$ carbon).
• Uses/hazards: $CHCl_3$ (anaesthetic, $\to$ phosgene), $CCl_4$, $CHI_3$ (antiseptic), DDT (persistent pesticide), freons (ozone-depleting).