Which statement is TRUE about hydrogen bonds and water molecules? Hydrogen bonds are a weak attraction between two hydrogen atoms Hydrogen bonds are a weak attraction between two different molecules of water Hydrogen bonds are a strong bond between a hydrogen atom and an oxygen atom in one molecule of water Hydrogen bonds are a weak attraction between atoms within one molecule of water
The Correct Answer and Explanation is:
The true statement about hydrogen bonds and water molecules is:
Hydrogen bonds are a weak attraction between two different molecules of water.
Explanation:
Water (H₂O) molecules have a unique ability to form hydrogen bonds due to the polarity of the water molecule. A water molecule consists of two hydrogen atoms covalently bonded to a central oxygen atom. The oxygen atom is more electronegative than hydrogen, meaning it pulls the shared electrons closer to itself, creating a partial negative charge on the oxygen and a partial positive charge on the hydrogen atoms.
Because of this polarity, the positively charged hydrogen atom of one water molecule is attracted to the negatively charged oxygen atom of another water molecule. This interaction is known as a hydrogen bond. It’s not a true chemical bond (like covalent bonds) but rather a weak intermolecular force. These hydrogen bonds are responsible for many of the unique properties of water, such as its high boiling point, surface tension, and the ability to dissolve a wide range of substances.
Why the other statements are false:
- “Hydrogen bonds are a weak attraction between two hydrogen atoms” – This is incorrect. A hydrogen bond involves the attraction between a hydrogen atom (which is covalently bonded to an electronegative atom, like oxygen) and another electronegative atom (like oxygen), not between two hydrogen atoms.
- “Hydrogen bonds are a strong bond between a hydrogen atom and an oxygen atom in one molecule of water” – This is incorrect. The bond between the hydrogen and oxygen atoms within a water molecule is a covalent bond, which is much stronger than a hydrogen bond. Hydrogen bonds occur between molecules, not within a single molecule.
- “Hydrogen bonds are a weak attraction between atoms within one molecule of water” – This is incorrect. Again, within one water molecule, the attraction between the hydrogen and oxygen atoms is a covalent bond, not a hydrogen bond. Hydrogen bonds form between different water molecules.
Therefore, the correct understanding is that hydrogen bonds form between different water molecules, and they are responsible for water’s cohesive and adhesive properties.
