Aldehydes

To solve the problem, we need to determine the correct prefix used for the aldehyde functional group in IUPAC nomenclature.

1. Understanding Functional Group Naming:
- The aldehyde group is represented as in organic chemistry.
- In IUPAC naming:
 • The suffix used is -al (e.g., ethanal, methanal)
 • The prefix used when the aldehyde is not the principal functional group is formyl

2. Evaluating the Options:
- (1) -al → suffix
- (2) -ol → suffix for alcohols
- (3) formyl → ✅ correct prefix for aldehydes
- (4) hydroxy → prefix for alcohols

Final Answer:
The prefix used for the aldehyde functional group is formyl.

To solve the problem, we need to identify the correct functional group that characterizes a carboxylic acid.

1. Understanding Functional Groups:
–CHO is the aldehyde group.
–COOH is the carboxylic acid group.
–CO– represents the ketone group (carbonyl group within a chain).
–COOR is the ester group.

2. Functional Group of Carboxylic Acid:
Carboxylic acids are defined by the presence of the –COOH group, which consists of both a carbonyl (C=O) and a hydroxyl (–OH) group attached to the same carbon atom.

Final Answer:
The functional group present in carboxylic acid is