Which of the following best explains why water is considered a polar molecule?

• A. Water contains ionic bonds between hydrogen and oxygen atoms.
• B. Water molecules are linear, causing the charges to be distributed equally.
• C. Water has an uneven distribution of electron density due to the difference in electronegativity between hydrogen and oxygen, resulting in a partial positive and partial negative end.
• D. Water is composed of identical atoms, so there is no difference in electronegativity.

Answer: (C)

Verified step by step guidance

1. Understand the concept of polarity in molecules: A molecule is polar if it has an uneven distribution of electron density, leading to partial positive and negative charges on different parts of the molecule.
2. Recall that polarity arises from differences in electronegativity between atoms bonded together. Electronegativity is the tendency of an atom to attract electrons towards itself in a chemical bond.
3. Examine the water molecule (H\_2O): Oxygen is more electronegative than hydrogen, so it pulls the shared electrons in the O-H bonds closer to itself, creating partial negative charges near oxygen and partial positive charges near hydrogen.
4. Consider the shape of the water molecule: It is bent (not linear), which means the dipole moments from each O-H bond do not cancel out, resulting in an overall polar molecule with distinct positive and negative ends.
5. Conclude that water's polarity is due to the combination of the difference in electronegativity between oxygen and hydrogen and the bent molecular geometry, leading to an uneven distribution of electron density.