Question

What is the general name of pentanal (${C_4}{H_9}CHO$) ?

Answer 1

Functional group: In the hydrogen the atoms or groups which are other than carbon and hydrogen, are known as function groups. For example: chloride if chlorine is present in the compound. And if $- CHO$ group is attached to any alkyl group then the suffix used is aldehyde or al.

Complete step by step solution:
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 ${C_n}{H_{(2n - 2)}}$.

Number of carbon atom in alkane	Name of the parent chain
One	Methane
Two	Ethane
Three	Propane
Four	Butane
Five	Pentane
Six	Hexane
Seven	Heptane

Functional group: In hydrogen the atoms or groups which are other than carbon and hydrogen, are known as function groups. For example: chloride if chlorine is present in the compound. And if $- CHO$ group is attached to any alkyl group then the suffix used is aldehyde or al.
Here we are given the IUPAC name of the compound and we have to find the general name of the compound.
General names of the compound are also known as common names. The general name of the compound is defined as the name by which that compound is known by others.
The general name of pentanal (${C_4}{H_9}CHO$) is Valeraldehyde.

Note: Suffix to some functional groups are as: for carboxylic acid suffix used is –oic acid, for alcohols suffix used is alkyl alcohol. For example: if an alcohol group is present in methane then the IUPAC name of the compound will be methyl alcohol.