Organic reactions are classifieds into four types they are:
i. Substitution reactions: Substitution reactions are a chemical reactions, during which one functional group in a chemical compound is replaced by another functional group these reactions is also known as substitution reactions.
Eg: alkanes reacts with halogens like Cl,Br,I etc to form alkyl halides.
CH4 + Cl2-------> CH3Cl + HCl
ii. Addition reactions: Addition reactions are a chemical reactions these reactions occurs only the compound containing double bonds or triple bonds the reaction is known as addition reactions.the two different reactants combinds to form large single product.
Eg: alkenes or alkynes undergoes addition reaction to form alkyl halides.
CH2=CH2 + HBr ----------> CH3-CH2-Br
iii. Elimination reactions: Elimination reactions are a organic reactions.in which two substituents are removed from a molecule ,in either one step or two step mechanism.one step mechanism is Known as E2 reaction and two step mechanism is known as E1 reaction.
Eg: alkyl halides undergoes elimination reaction to produce alkenes.
CH3-CH2-Cl ----------> CH2=CH2 + HCl
iv. Rearrangement reactions: In rearrangement reactions oximes undergoes rearrangement reactions in the presence of acid catalyst like conc.H2SO4 to form N- substituted amides.
Eg: Acetophenone oxime undergoes anti migration in the presence of acid catalyst to form acetanilide.
Conc.
H2SO4
CH3-C-C6H5=N-OH ------------>CH3-CO-NH-C6H5.