Reagent Reference
Know your reagents. Colour-coded by the reaction type they drive.
Oxidising Agents
- KMnO₄
Strong oxidiser — alcohols → acids, cleaves double bonds.
- K₂Cr₂O₇
Strong oxidiser (acidic) — 1° alcohol → acid, 2° → ketone.
- O₃ (ozonolysis)
Cleaves C=C to two carbonyls.
- CrO₃
Strong oxidiser; Jones-type oxidations.
- PCC (mild)
Mild — 1° alcohol → aldehyde (stops there).
Reducing Agents
- LiAlH₄
Strong — reduces acids, esters, nitriles, carbonyls.
- NaBH₄
Mild — reduces aldehydes & ketones, not acids/esters.
- H₂ / Ni
Catalytic hydrogenation of C=C, C≡C.
- H₂ / Pd
Catalytic hydrogenation; Pd/BaSO₄ (Rosenmund) for acyl chloride → aldehyde.
Halogenating Agents
- Cl₂
Free-radical (hv) substitution on alkanes; addition to alkenes.
- Br₂
Addition to C=C (decolourises); substitution with hv.
- SOCl₂
–OH → –Cl (alcohols, acids → acyl chloride). Clean by-products.
- PCl₅
–OH → –Cl; also acids → acyl chlorides.
- PBr₃
Alcohols → alkyl bromides.
Bases
- KOH (aq)
Aqueous → nucleophilic substitution (haloalkane → alcohol).
- KOH (alc)
Alcoholic → elimination (haloalkane → alkene).
Nucleophiles
- OH⁻
→ alcohols (substitution).
- CN⁻
→ nitriles (chain extension by one carbon).
- NH₃
→ amines (ammonolysis).
- RO⁻
→ ethers (Williamson synthesis).
Electrophiles
- H⁺
Protonates double bonds (Markovnikov addition).
- Br⁺
Electrophilic bromination of arenes/alkenes.
- NO₂⁺
Nitronium ion — aromatic nitration.
- SO₃
Aromatic sulfonation.