Question

Which of the following compounds exhibits the maximum hydrogen bonding in the liquid state?

• A. \(CH_3OH\)
• B. \(HF\)
• C. \(H_2O\)
• D. \(NH_3\)

Hint:

Water is unique because each molecule can form four hydrogen bonds simultaneously, producing an extensive intermolecular network responsible for its unusually high boiling point.

Answer 1

The Correct Option is C

Concept: Hydrogen bonding occurs when hydrogen is attached to highly electronegative atoms such as F, O, or N. The extent of hydrogen bonding depends on the number of hydrogen bond donors and acceptors available.

Step 1: Analyze water. Water molecule: \[ H_2O \] contains:
• Two hydrogen atoms capable of donation
• Two lone pairs on oxygen capable of acceptance Thus one water molecule can participate in four hydrogen bonds.

Step 2: Analyze HF. HF forms strong hydrogen bonds but each molecule possesses only one hydrogen atom. Hence the network is less extensive than water.

Step 3: Analyze ammonia. Ammonia contains one lone pair and three hydrogen atoms. However nitrogen is less electronegative than oxygen. Therefore hydrogen bonding is weaker.

Step 4: Analyze methanol. Methanol forms hydrogen bonds but only through one hydroxyl group. Its hydrogen bonding network is less extensive. Conclusion: Water develops the most extensive three-dimensional hydrogen-bonded network. Hence maximum hydrogen bonding occurs in: \[ H_2O \] Therefore option (C) is correct.