Which of the following best explains why water (H2O) is a polar molecule?

• A. Water contains only nonpolar covalent bonds.
• B. Water has a linear molecular geometry.
• C. Water molecules are held together by ionic bonds.
• D. Water has a bent molecular shape and an unequal sharing of electrons between oxygen and hydrogen atoms.

Answer: (D)

Verified step by step guidance

1. Understand that molecular polarity depends on both the polarity of individual bonds and the shape of the molecule.
2. Recognize that the O-H bonds in water are polar because oxygen is more electronegative than hydrogen, causing unequal sharing of electrons.
3. Identify the molecular geometry of water as bent (or V-shaped) due to the two lone pairs on oxygen, which affects the overall distribution of charge.
4. Combine the effects of polar O-H bonds and the bent shape to see that the dipole moments do not cancel out, resulting in a net dipole moment.
5. Conclude that water is polar because it has polar bonds arranged in a bent shape, leading to an uneven distribution of charge across the molecule.