Which major IR absorption is expected for a compound containing a carbonyl group?

• A. A strong absorption near $3300\mathrm{cm}{-}^1$ due to the O-H stretch
• B. A strong absorption near $1600\mathrm{cm}{-}^1$ due to the aromatic C=C stretch
• C. A strong absorption near $2250\mathrm{cm}{-}^1$ due to the C≡N stretch
• D. A strong absorption near $1700\mathrm{cm}{-}^1$ due to the C=O stretch

Answer: (D)

Verified step by step guidance

1. Identify the functional group in the compound, which is the carbonyl group (C=O).
2. Recall that the carbonyl group has a characteristic infrared (IR) absorption due to the stretching vibration of the C=O bond.
3. Know that the C=O stretch typically appears as a strong, sharp absorption band in the IR spectrum around 1700 cm\textsuperscript{-1}.
4. Compare this with other common IR absorptions: O-H stretches appear near 3300 cm\textsuperscript{-1}, aromatic C=C stretches near 1600 cm\textsuperscript{-1}, and C≡N stretches near 2250 cm\textsuperscript{-1}.
5. Conclude that the major IR absorption expected for a compound containing a carbonyl group is the strong absorption near 1700 cm\textsuperscript{-1} due to the C=O stretch.