How many hydrogen bonds can a single water (H_2O) molecule form simultaneously?

• A. 5
• B. 2
• C. 3
• D. 4

Answer: (D)

Verified step by step guidance

1. Understand that hydrogen bonding occurs when a hydrogen atom covalently bonded to a highly electronegative atom (like oxygen) interacts with a lone pair of electrons on another electronegative atom.
2. Recognize that a water molecule (H\_2O) has two hydrogen atoms, each capable of donating one hydrogen bond because the hydrogen is partially positive and can interact with lone pairs on other molecules.
3. Note that the oxygen atom in water has two lone pairs of electrons, each capable of accepting one hydrogen bond from hydrogen atoms of neighboring molecules.
4. Combine these facts: the water molecule can donate two hydrogen bonds (one from each hydrogen) and accept two hydrogen bonds (one for each lone pair on oxygen).
5. Conclude that a single water molecule can form a total of 4 hydrogen bonds simultaneously—2 as a donor and 2 as an acceptor.