Organic Textbook pg69

[704578485]

In the organic textbook on page 69, the naming of ketones is desctibed. Why on the structure that is labeled as butanone is it not 2butanone? Isnt the functional group part of the 2nd carbon in the chain?

[Chem_Mod]

Yes, but just remember that it will only have one structure in the end. By definition, a ketone must be located inside of the carbon chain. Therefore, it can only be at positions 2 or 3. Since the chain is only four carbons long, 2-butanone is the exact same as 3-butanone. Since there is only one possible structure of 2-butanone, the number is dropped bc it is redundant.

[704578485]

If you were to put 2-butanone on an exam would it be marked as incorrect?

[Chem_Mod]

Correct. Either works because it would give the same answer (but yes it is fine :D)