What is the structure of 1-buten-3-one?

The structure of 1-buten-3-one can be understood by breaking down its name according to the rules of organic nomenclature. The name indicates that it is an unsaturated compound with a double bond and a carbonyl group (a C=O connection).

1-buten-3-one specifically describes a four-carbon chain ("buten") with the double bond located between the first and second carbon atoms, and a carbonyl group on the third carbon. The notation "1-buten" tells us that the double bond starts at the first carbon, while the "3-one" indicates the presence of a carbonyl group on the third carbon.

Thus, the correct structure starts with a double bond between the first carbon (C1) and the second carbon (C2): CH₂=CH-. This portion represents the butene part. Following that, on the third carbon (C3), we have a carbonyl group (C=O) which connects to another carbon that is part of a methyl group (C4). This leads to the complete structural representation: CH₂=CH-C(=O)-CH₃.

This structure perfectly matches the provided option, showing that it contains a double bond and a carbonyl group