Which of the following functional groups does Butanal belong to?

Butanal is an organic compound that contains "-al" as a suffix in its name. We know that organic compounds which contain the "-al" suffix belong to the aldehyde functional group. Thus, our answer to the question will be option "B". In the rest of the options, the suffix is "-ol" for Alcohol, "-one" for Ketone, and "-oic aid" for the carboxylic acid functional group.