Question

in water, what causes the formation of hydrogen bonds? 1 attraction between the partially positive oxygen of one water molecule and the partially negative hydrogen of a different water molecule. 2 sharing of a pair of electrons between the hydrogen atom and the oxygen atom. 3 attraction between the partially negative oxygen of one water molecule and the partially positive hydrogen of a different water molecule. 4 sharing of a pair of electrons between two hydrogen atoms.

Explanation:

Hydrogen bonds in water form due to the attraction between the partially negative oxygen of one water molecule and the partially positive hydrogen of another water molecule. Let's analyze each option:

• Option 1: Incorrect. Oxygen is partially negative, hydrogen is partially positive, so the attraction is not between partially positive oxygen and partially negative hydrogen.
• Option 2: This describes a covalent bond within a water molecule (between H and O), not a hydrogen bond between molecules.
• Option 3: Correct. The partially negative O of one $H_2O$ and partially positive H of another $H_2O$ attract, forming H - bonds.
• Option 4: Describes a covalent bond between two H atoms, not related to water's hydrogen bonds.

Answer:

1. Attraction between the partially negative oxygen of one water molecule and the partially positive hydrogen of a different water molecule.