Q. Which of the following are classified as ketones?

1. Acetone
2. Formaldehyde
3. Acetic acid
4. Isopropanol

Select the correct option using the codes below:
Answer: Only 1
Notes: Acetone ((CH₃)₂CO) is the simplest ketone. Formaldehyde (HCHO) is an aldehyde, acetic acid (CH₃COOH) is a carboxylic acid, and isopropanol (C₃H₇OH) is an alcohol. Hence, among the options, only acetone is a ketone; the others belong to different functional groups.