Nomenclature, Nature of Carbonyl Group — Prelims Questions

Which of the following compounds is correctly named according to IUPAC rules?

What is the IUPAC name for the compound $CH_3-CH_2-CO-CH(CH_3)-CH_3$?

Which of the following statements about the carbonyl group is INCORRECT?

What is the common name for methanal?

What is the IUPAC name of the following compound: $C_6H_5-CO-CH_2-CH_3$?

Which of the following pairs represents functional isomers?