Which of the following statements is correct about naming a ketone according to IUPAC nomenclature?

• A. The prefix $\mathrm{oxo-}$ is always used in naming simple ketones.
• B. The carbonyl group in a ketone is always located at the end of the carbon chain.
• C. The suffix $\mathrm{-al}$ is used to indicate the presence of a ketone group.
• D. The parent chain is numbered so that the carbonyl carbon receives the lowest possible number.

Answer: (D)

Verified step by step guidance

1. Understand that in IUPAC nomenclature for ketones, the carbonyl group (C=O) is a key functional group that must be properly identified and located within the parent carbon chain.
2. Recall that the carbonyl group in ketones is never at the end of the carbon chain; if it were, the compound would be an aldehyde, not a ketone.
3. Know that the suffix used for ketones is '-one', not '-al' (which is reserved for aldehydes), and the prefix 'oxo-' is used only when the ketone group is a substituent, not in simple ketones where the ketone is the main functional group.
4. Apply the rule that the parent chain must be numbered in such a way that the carbonyl carbon receives the lowest possible number, ensuring correct and unambiguous identification of the ketone position.
5. Use this numbering to name the ketone by combining the parent alkane name with the suffix '-one' and the appropriate locant indicating the position of the carbonyl group.