Functional Groups C CC C C Br CH H C Cl CC C C O H CH C C I alkenealkynetertiary halogenoalkane secondary halogenoalkane primary halogenoalkane tertiary alcohol

Functional groups CH C C N HH CH C C N H CH C C N C C O H O C C O C primary amine secondary amine tertiary amine etheraldehydeketone

Functional groups C O O H O O C O O O O Cl C O N carboxylic acidester amide acid anhydrideacyl chloride C N nitrile

Functional groups H O arene (benzene ring)phenol

Free Radical substitution CHH H H Cl 2 Cl· Initiation Propagation +Cl· C·C·H H H + HCl C·C·H H H Cl C H H H + Cl· +

C·C·H H H ·Cl C ClH H H Cl· ·Cl Cl ·C·CH H H C·C·H H H CH H H CH H H Free Radical Substitution Termination

 H (kJ mol -1 ) E act (kJ mol -1 ) Chain initiation F 2  2 F · +160 Chain propagation F · + CH 4  HF + CH 3 · CH 3 · + F 2  CH 3 F + F· -294small Overall 2 F 2 + CH 4  HF +CH 3 F -428

 H (kJ mol -1 ) E act (kJ mol -1 ) Chain initiation Cl 2  2 Cl · +244 Chain propagation Cl · + CH 4  HCl + CH 3 · CH 3 · + Cl 2  CH 3 Cl + Cl · -107small Overall 2 Cl 2 + CH 4  HCl +CH 3 Cl -103

 H (kJ mol -1 ) E act (kJ mol -1 ) Chain initiation Br 2  2 Br · +193 Chain propagation Br · + CH 4  HBr + CH 3 · CH 3 · + Br 2  CH 3 Br + Br · -101small Overall 2 Br 2 + CH 4  HBr +CH 3 Br -32

 H (kJ mol -1 ) E act (kJ mol -1 ) Chain initiation I 2  2 I · +151 Chain propagation I · + CH 4  HI + CH 3 · CH 3 · + I 2  CH 3 I + I · -84small Overall 2 I 2 + CH 4  HBr +CH 3 I +46

 bonding in alkenes CC H H H H Two adjacent p orbitals overlap to produce a  bond The exposed  electron pair can be attacked by electrophiles. An electrophile is a species with an empty orbital that can accept a pair of electrons.

Electrophilic addition to alkenes ReagentElectrophile (in bold) Product of reaction with propene Br 2 (in organic solvent) Br  +  - CH 3 CHBrCH 2 Br Br 2 (aq)CH 3 CH(OH)CH 2 Br HBr H+H+ CH 3 CHBrCH 3 cold H 2 SO 4 (l)CH 3 CH(OSO 3 H) CH 3

Addition of HBr to propene C CH 3 H HH H Br  +  C CH 3 H HH H + Br - C CH 3 H HH HBr Markovnikov’s rule: The less electronegative atom (H) adds to the carbon atom of the double bond with most H atoms attached. This gives rise to a more stable carbocation intermediate (order of stability 1°<2°<3°)

Addition of Br 2 to propene C CH 3 H HH Br  +  C CH 3 H HH Br + Br - C CH 3 H HH Br Br 2 is non-polar but as it approaches the  bond, a dipole is induced.

Addition of Br 2 (aq) to propene C CH 3 H HH Br  +  C CH 3 H HH Br + Br - OH 2 C CH 3 H HH BrH2OH2O + C CH 3 H HH BrHO H + (aq)

Other alkene reactions Addition of hydrogen CH 3 CH=CH 2 + H 2 (g) → CH 3 CH 2 CH 3 (Ni catalyst, 200°C) Oxidation CH 3 CH=CH 2 CH 3 CH(OH)CH 2 OH Purple KMnO 4 (aq) is decolourised by alkenes KMnO 4 (aq), H 2 SO 4 (cold)