Question
All of the following statements help to explain why water molecules form hydrogen bonds except:- The electrons spend more time around the oxygen atom because oxygen is more electronegative than hydrogen.- Attractions form between opposite partial charges.- Water is an electronegative molecule.- There is a partial positive charge on each hydrogen atom and two partial negative charges on the oxygen atom in a water molecule.
Answer
The statement that does not explain hydrogen bonding is:
Water is an electronegative molecule.
Why that statement is incorrect
Electronegativity is a property used to compare how strongly atoms attract shared electrons in a covalent bond. Oxygen is more electronegative than hydrogen, so the electrons in each O–H bond spend more time near oxygen. This gives the oxygen end partial negative character and the hydrogen ends partial positive character.
The water molecule is therefore described as polar, not electronegative.
Why the other statements help
- Oxygen's stronger attraction for the shared electrons creates unequal electron distribution.
- Opposite partial charges on neighboring water molecules attract one another.
- The partially positive hydrogen of one water molecule can interact with the partially negative oxygen region of another, forming a hydrogen bond.
The original choice refers to “two partial negative charges” on oxygen. More precisely, one oxygen atom has partial negative character; its electron-rich region and lone pairs allow it to accept hydrogen bonds.
Evidence boundary
The answer preserves the wording of this four-choice question version. It interprets the option about two partial negative charges as referring to the oxygen end's partial negative character; it does not assert that a water molecule contains two separate full negative charges.
Sources
These references support the concepts and methods used in the explanation above.