Question

What is the IUPAC name for ${\mathrm{CH}}_3\mathrm{CHO}$?

Answer 1

Aldehyde:

• Aldehyde is a functional group in which the $-\mathrm{CHO}$ group is directly attached to the hydrocarbon.
• The general formula of alcohol is, $\mathrm{R}-\mathrm{CHO}$.

The basic rules for naming aldehyde are:

• The longest possible chain should contain $-\mathrm{CHO}$ group.
• The name of longest chain is given by suffix$‘-\mathrm{al}’$.
• During numbering of carbon chain, always give lowest number to carbon bearing the $-\mathrm{CHO}$ group.
• The number before the suffix $‘-\mathrm{al}’$ represents the position of aldehyde group but locant number 1 before suffix $‘-\mathrm{al}’$ can be used or not.

In the given compound, the longest possible carbon chain has two carbon atoms. So, the prefix used will be $\text{'}\mathrm{eth}-\text{'}$ and also the carbon has $-\mathrm{CHO}$ group, so it is an aldehyde and the suffix used will be $‘-\mathrm{al}’$.

Hence, the IUPAC name for ${\mathrm{CH}}_3\mathrm{CHO}$ is Ethanal.