Which of the following statements helps to explain why water molecules form hydrogen bonds?

Question

Attractions form between opposite partial charges.
There is a partial negative charge on each hydrogen atom and two partial positive charges on the oxygen atom in a water molecule.
Water is an electronegative molecule.
The electrons spend more time around the hydrogen atoms because hydrogen is more electronegative than oxygen.

Answer 1

The statement that best explains why water molecules form hydrogen bonds is:

Attractions form between opposite partial charges.

This statement highlights the nature of hydrogen bonds, which arise from the attractive forces between the partial positive charge on the hydrogen atoms of one water molecule and the partial negative charge on the oxygen atom of another water molecule.

To clarify the other options:

• The second statement is incorrect as it misrepresents the charges: water has a partial positive charge on the hydrogen atoms and a partial negative charge on the oxygen atom.
• The third statement is misleading; water is a polar molecule, but saying it is "electronegative" is not accurate for the molecule as a whole.
• The fourth statement is incorrect because oxygen is more electronegative than hydrogen, not the other way around.

So, the first statement correctly describes the basis for hydrogen bonding in water.