(i) Wurtz reaction – when alkyl halide is allowed to react with metallic sodium in presence of dry ether an alkane is obtained.
(ii) Kolbes reaction – When a solution of sodium acetate is electrolized, ethane is obtained.
(iii) Ozonolysis of alkene: When an alkene is allowed to react with ozone, an ozonide is obtained. This on hydrolysis gives Aldehyde or ketone. The whole process is called ozonolysis.