• A functional group is an atom or group of atoms in a molecule that gives the molecule its characteristic chemical properties i.e. they are the action group or reactive site in a chemical reaction and the remaining hydrocarbon part remains inert.
• Each functional group shows its characteristic chemical reactions.
• Functional group helps in nomenclature of organic compounds.
• Functional group serves to classify organic compounds into different classes or families i.e. compounds with same functional group belong to same class.
Different functional groups
• Functional group with ó bond only: C-C/H Alkane, C-X Alkyl halide, C-OH Alcohol, C-O-C Ether, C- NH2 Amine, C-SH Thiol, C-S-C Thioether etc.
• Functional group with one ð bond: • Along C=O bond: CHO Aldehyde, COC Ketone, COX Acid halide, COOH Carboxylic acid, COOC Ester, COOCOC Acid anhydride, CONH2 Amide
• Along C=N bond derieved from aldehyde or ketones C=N-H Imine, C=N-OH Hydroxyl amine, C=N-NH2 Hydrazene, C=N-NHPh Phenyl hydrazene etc.
• Along C=C bond. C=C Alkene
• Functional group with two ð bond. C≡C Alkyne, C ≡N Nitrile, N≡C Isonitrile
