Final answer:
H₂O is polar due to its bent structure causing a net dipole moment, while CO₂ is nonpolar because its linear shape results in dipole cancellation.
Step-by-step explanation:
Among the molecules listed, H₂O (water) is polar, and CO₂ (carbon dioxide) is nonpolar. The polarity of a molecule depends not only on the electronegativity difference between atoms but also on the molecular geometry. In the case of CO₂, the molecule is linear, and the individual dipoles from the carbon atom to each oxygen atom cancel out, making the molecule nonpolar. Conversely, H₂O has a bent structure due to the two lone pairs on the oxygen, which causes the dipoles from the hydrogen atoms to the oxygen atom not to cancel out, resulting in a polar molecule with a net dipole moment.