Hydrogen bonding in molecules

Steps:

• Identify molecules capable of hydrogen bonding: those with H attached to N, O, or F, and lone pairs on electronegative atoms.
• Evaluate each option: check if listed molecules (1-4) form H-bonds affecting properties like boiling point or solubility.
• Not enough information: molecules 1-4 are not specified, preventing precise identification.
• Conclude based on given correct answer, but explanation limited by missing details.

Why C is correct:

• Assumes 1 and 3 have H-bonding groups (e.g., O-H or N-H), per definition of hydrogen bonds as attractions between partial charges.

Why the others are wrong:

• A includes 2, which lacks H-bond capability if non-polar or without key atoms.
• B includes 4, likely without H-bonding electronegative atoms.
• D excludes 1 and 3, missing key H-bond dependent molecules.

Final answer: C