Which of the following functional groups is commonly involved in hydrogen bonding due to its ability to donate a hydrogen atom?

• A. Methyl group ($-C_{\mathrm{H}}3$)
• B. Hydroxyl group ($-OH$)
• C. Nitro group ($-N{O}_2$)
• D. Carbonyl group ($C=O$)

Answer: (B)

Verified step by step guidance

1. Identify the functional groups listed in the problem: Methyl group (-CH3), Hydroxyl group (-OH), Nitro group (-NO2), and Carbonyl group (C=O).
2. Understand the concept of hydrogen bonding: Hydrogen bonding occurs when a hydrogen atom, covalently bonded to a highly electronegative atom like oxygen, nitrogen, or fluorine, interacts with another electronegative atom.
3. Analyze each functional group for the presence of a hydrogen atom bonded to an electronegative atom: The hydroxyl group (-OH) has a hydrogen atom bonded to an oxygen atom, which is highly electronegative.
4. Compare the ability of each functional group to participate in hydrogen bonding: The hydroxyl group can donate a hydrogen atom for hydrogen bonding due to the presence of the O-H bond.
5. Conclude that the hydroxyl group (-OH) is commonly involved in hydrogen bonding because it can donate a hydrogen atom, unlike the other groups listed.