Question

Write the IUPAC name of the following compounds:
A) ${\left( {C{H_3}} \right)_2}CHCH\left( {Cl} \right)C{H_3}$
B) $C{H_3}C{H_2}C{\left( {C{H_3}} \right)_2}C{H_2}I$
C) $C{H_3}CH\left( {C{H_3}} \right)CH\left( {Br} \right)C{H_3}$
D) $C{H_3}C\left( {Cl} \right)\left( {{C_2}{H_5}} \right)C{H_2}C{H_3}$
E) $C{H_3}CH = CHC\left( {Br} \right){\left( {C{H_3}} \right)_2}$

Answer 1

The IUPAC or the International Union of Pure and Applied Chemistry has set out some rules for the nomenclature of the organic compounds, based on which the compounds are named. The longest chain is regarded as the parent chain and the substituent groups or double and triple bonds are assigned the lowest number possible in the chain.

Complete step by step solution:
I) In the first compound, there are four carbon atoms in the main chain, therefore, the root name is ‘but’. Now according to the alphabetical order, the substituent that comes first is the chloro group, followed by the methyl group. So the name of the compound is:
2-Chloro 3-Methyl Butane
II) In the second compound, there are four carbon atoms, so the root is ‘but’ and as per the substituents the IUPAC name is: 1-iodo (2, 2) dimethyl butane.
III) In the third compound, there are four carbon atoms, so the root name is ‘but’ and as per the substituents the name is: 2-Bromo 3-Methyl Butane
IV) In the fourth compound, there are four carbon atoms there are four carbon atoms, hence the root name is ‘but’ and with the substituents the name is:
2-chloro 2-ethyl butane.
V) In the fifth compound, there is a double bond at the second carbon atom and hence the name will end with ‘ene’ and there are five carbon atoms for the root is ‘pent’, so the name is: 4-Bromo 4-Methyl pent-2-ene.

Note:
The nomenclature of the compounds is dependent upon the priority of the substituents attached to the carbon atoms. The triple bond gets more preference over a double bond which gets more preference over a single bond in terms of nomenclature.