Question

Draw structure of $4 - {\text{ethyl}}3 - {\text{methyloctane}}$.

Answer 1

Hint:In IUPAC we have to first find the largest chain i.e. parent chain then if there is any branching in the parent chain then mark the number in the way so that the atom from which branching is happening gets a lower number and then accordingly write the name.

Complete step by step answer:
First of all we will talk about the alkanes, alkenes and alkynes.
Alkanes: The compounds which are formed by carbon and hydrogen and have only a single bond between the carbon-carbon atoms, are known as alkanes. For example: The first member of the alkane family is ethane $({H_3}C - C{H_3})$. The general formula of the alkane group is ${C_n}{H_{(2n + 2)}}$.
Alkenes: The compounds which are formed by carbon and hydrogen and have at least one double bond along with a single bond between the carbon-carbon atoms, are known as alkenes. For example: The first member of the alkene family is ethene $({H_2}C = C{H_2})$. The general formula of the alkene group is ${C_n}{H_{2n}}$.
Alkynes: The compounds which are formed by carbon and hydrogen and have at least one triple bond along with a single bond between the carbon-carbon atoms, are known as alkynes. For example: The first member of the alkyne family is ethyne $(HC \equiv CH)$. The general formula of the alkyne group is ${C_n}{H_{(2n - 2)}}$.
Now here we have to draw the structure of $4 - {\text{ethyl}}3 - {\text{methyloctane}}$. Here octane is the parent chain so it is clear that hydrogen must have at least $8$ carbon atoms. Now there are two branches given here i.e. at fourth position ethyl group is present and at third position methyl group is present so the structure will be as: ${\text{C}}{{\text{H}}_{\text{3}}}{\text{C}}{{\text{H}}_{\text{2}}}{\text{CH(C}}{{\text{H}}_{\text{3}}}{\text{)CH(}}{{\text{C}}_{\text{2}}}{{\text{H}}_{\text{5}}}{\text{)C}}{{\text{H}}_{\text{2}}}{\text{C}}{{\text{H}}_{\text{2}}}{\text{C}}{{\text{H}}_{\text{2}}}{\text{C}}{{\text{H}}_{\text{3}}}$. And numbering should be from the left side because from the left side number at branching comes first.

Note:
The term iso- stands for isomer and is usually used when there is one methyl group located on the second carbon i.e. three carbon attached to the second carbon of a carbon chain. And the term neo pentane means that four Carbon atoms are attached to one atom.