Question

Draw the structure of an alkane or cycloalkane that has more than three but fewer than ten carbon atoms, and only primary hydrogens. (There are several possible structures. It is enough to draw any one of them, but you may draw two or more if you want to.)

Answer 1

Concept and reason

The hydrogen atom connected to a carbon atom, which is connected to another carbon atom is called as primary hydrogen atom. Primary hydrogen atom is denoted as ${1^{\rm{o}}}$ hydrogen.

Check the possible straight chain and branched alkanes/cycloalkanes with more than three and less than nine carbon atoms and draw one possible structure containing only primary hydrogens (if the hydrogen atom present on a carbon atom which is bonded with other carbon atom) for both alkane and cycloalkane.

Fundamentals

Alkanes contain only linear and branched chains of carbon atoms. The molecular formula of alkanes is ${{\rm{C}}_n}{{\rm{H}}_{2n + 2}}$ . Here, n is the integer.

Cycloalkanes contain one or more rings. The molecular formula for cycloalkanes is ${{\rm{C}}_n}{{\rm{H}}_{2n}}$ . Here, n is the integer.

If the hydrogen atom present on a carbon atom which is bonded with other carbon atom, then that hydrogen is known as primary ( $1^\circ$ ) hydrogen.

If the hydrogen atom present on a carbon atom which is bonded with other two carbon atom, then that hydrogen is known as secondary ( $2^\circ$ ) hydrogen.

If the hydrogen atom present on a carbon atom which is bonded with other three carbon atom, then that hydrogen is known as tertiary ( $3^\circ$ ) hydrogen.

The possible structures are as follows:

Draw the possible branched chain alkane which contains only primary hydrogens as follows:

Draw the possible branched cycloalkanes which contain only primary hydrogens.

Ans:

Thus, the structure of an alkane and cycloalkane that contains only primary hydrogens with more than three and less than nine carbon atoms are as follows: