Question

Fill in the gaps in the table of homologous series.

Accepted Answer

A homologous series is a series that has compounds with the same functional group and each member is differed by ${CH}_{2}$ group. The members of the series are called homologues. A general formula is used to represent each homologous series. Thus, the alkane series is also a homologous series with the general formula $C_{n} H_{2 n + 2}$ and each member will differ by a ${CH}_{2}$ group.

Butane with the chemical formula $C_{4} H_{10}$ has four carbon atoms as the IUPAC name butane indicates that the parent chain consists of four carbon atoms and hence the root word is 'but'. All the valencies of carbon atoms are satisfied by single bonds as the root word ends with 'ane'. It has the condensed structural formula ${CH}_{3} - {CH}_{2} - {CH}_{2} - {CH}_{3}$ and therefore has 4 ${CH}_{2}$ groups.

Pentane with the chemical formula $C_{5} H_{12}$ has five carbon atoms as the IUPAC name pentane indicates that the parent chain consists of five carbon atoms and hence the root word is 'pent'. All the valencies of carbon atoms are satisfied by single bonds as the root word ends with 'ane'. It has the condensed structural formula ${CH}_{3} - {CH}_{2} - {CH}_{2} - {CH}_{2} - {CH}_{3}$ and therefore has 5 ${CH}_{2}$ groups.

Hexane with the chemical formula $C_{6} H_{14}$ has six carbon atoms as the IUPAC name hexane indicates that the parent chain consists of six carbon atoms and hence the root word is 'hex'. All the valencies of carbon atoms are satisfied by single bonds as the root word ends with 'ane'. It has the condensed structural formula ${CH}_{3} - {CH}_{2} - {CH}_{2} - {CH}_{2} - - {CH}_{2} - {CH}_{3}$ and therefore has 6 ${CH}_{2}$ groups.

The complete table is given below:

Maharashtra Board Solutions for Chapter: Carbon Compounds, Exercise 9: Complete the table

Maharashtra Board Science and Technology Solutions for Exercise - Maharashtra Board Solutions for Chapter: Carbon Compounds, Exercise 9: Complete the table

Questions from Maharashtra Board Solutions for Chapter: Carbon Compounds, Exercise 9: Complete the table with Hints & Solutions

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