in colour. If the given compound is unsaturated, it will decolourise bromine water. Saturated compounds do not decolourise bromine. ALKANE ADDITION OF BROMINE WATER TO ALKANES AND ALKENES Does not react with bromine water, and does not decolourise bromine water ALKENE Will react with bromine water, and as such also decolourises bromine water Figure .
Test to identify unsaturated compounds . . Classification of organic compounds based on functional groups The structural frameworks of organic compounds are made of carbon and hydrogen, which are relatively less reactive. But, the presence of some other atoms or group of atoms makes the compounds more reactive and thus determines the chemical properties of the compound.
These groups are called functional groups. A functional group is an atom or group of atoms in a molecule, which gives its characteristic chemical properties. The chemical properties of an organic compound depend on its functional group whereas its physical properties rely on remaining part of the structure. Carbon to carbon multiple bonds (C=C, C C) also are considered as functional groups as many of the properties are influenced by these bonds.
Other functional groups include, –OH, –CHO, –COOH, etc. For example, ethane is a hydrocarbon having molecular formula C H . If one of its hydrogen is replaced by –OH group, you will get an alcohol. Leaving the functional group, the rest of the structure is represented by ‘ R’.
Thus an alcohol is represented by ‘R-OH’ CH -CH CH -CH -OH Ethane Ethanol Hydrocarbon Alcohol Functional Group A series of compounds containing the same functional group is called a class of organic compounds. Table . shows various classes or families of organic compounds and their functional groups: Carbon and its Compounds . HOMOLOGOUS SERIES Homologous series is a group or a class of organic compounds having same general formula and similar chemical properties in which the successive members differ by a - CH group.
Let us consider members of alkanes given in Table . . Their condensed structural formulas are given below: Methane CH