Characteristics of organic compounds
Organic compounds have the following general characteristics.
i) Organic compounds are generally covalent and hence they do not dissolve in water (polar solvents) but dissolve in organic solvents (non-polar solvents) such as ether, alcohol, benzene etc.
ii) Due to maximum catenation and tetravalency of carbon, they have tendency to form long open and closed chain compounds.
iii) They are volatile, inflammable and possess low boiling points and melting points.
iv) Some organic compounds exhibit the phenomenon of polymerisation. For example, ethylene polymerises to poly ethylene.
v) They exhibit isomerism.
vi) They contribute homologous series.
vii) They are non-conductors of electricity.
Need for purification of organic compounds
The organic compounds obtained from natural sources are not pure. They contain a number of other compounds which occur with them. Similarly, the organic compounds prepared in the laboratory are also not pure. They are found to contain other products formed during the reaction. In order to investigate the structure and properties of an organic compound, it should be in the purest form. Hence purification of organic compounds become essential.
Various methods used for purification and separation of organic compounds are:
ii) Fractional Crystallisation