What is the IUPAC name for a compound with the structure CH3-CH2-CO-CH2-CH3?

The compound CH3-CH2-CO-CH2-CH3 is a ketone, as it features a carbonyl group (C=O) that is flanked by two carbon chains. In naming this molecule according to IUPAC conventions, one must first identify the longest continuous carbon chain that contains the carbonyl group.

In this case, the longest chain consists of five carbon atoms, which classifies the base name of the compound as "pentan". The position of the carbonyl group is essential for proper nomenclature. The carbonyl group is located at the second carbon when counting from either end of the chain, making it "pentan-2-one." This naming indicates that the carbonyl group is on the second carbon of the pentane chain, which is essential for clarity in organic nomenclature.

The other choices refer to incorrect placements of the carbonyl group. For example, "pentan-1-one" would imply the carbonyl is at the terminal position, which is not the case here. "Pentan-3-one" would suggest the carbonyl group is on the third carbon, which again does not match the structure given. Lastly, "cyclopentanone" refers to a cyclic compound with