Question

The suffix used for naming an aldehyde is:
(A) -ol
(B) -al
(C) -one
(D) -ene

Answer 1

Hint: Aldehyde is a functional group in the class of organic compounds. Take an example of an aldehyde along with its IUPAC name. Now split the name into root words and suffixes. Now you can identify the suffix used for aldehyde.

Complete step-by-step answer:
Functional groups consist of specific grouping of atoms within molecules that have their own distinguishing properties, regardless of the atoms present in a molecule. Few examples are amine, alcohol, carboxylic acid, ketones etc.
Aldehydes are compounds consisting of the characteristic terminal carbonyl structure. They are the next ones after carboxylic acid in the list of priority of functional groups.
We will take an example of aldehyde and then find the suffix used to denote the aldehyde functional group.
Compound: Ethanal
The root word is ethane. So, the suffix added to ethane is -al.

Thus, the suffix used for aldehydes is -al as specified by the International Union of Pure and Applied Chemistry.

Additional information: The International Union of Pure and Applied Chemistry is an international federation of National Adhering Organizations that represents chemists in the individual countries. IUPAC is registered in Zürich; Switzerland and its administrative office is called IUPAC secretariat.

Note: When more than one functional group is present in the same organic compound, there is a set priority for each functional group. Carboxylic acid group has the most priority and the least priority is assigned to the halogen atom functional group. So, when carboxylic acid group and aldehyde are present, we have to use a prefix to denote aldehyde group. Thus, the prefix for the aldehyde functional group as defined by the IUPAC is -formyl.