Chemistry

Question Analysis
This question involves the core concepts of bond polarity and molecular polarity, including the judgment criteria for polar bonds, nonpolar bonds, polar molecules, and nonpolar molecules. 

Key Concept Explanation
Nonpolar covalent bond: Formed between atoms of the same element (e.g., H-H, O=O).
Polar covalent bond: Formed between atoms of different nonmetallic elements (e.g., H-Cl).
Rule: The larger the electronegativity difference between bonded atoms, the more polar the covalent bond.

Molecular polarity depends on the polarity of individual bonds, and the molecular geometry (symmetry).

Option Analysis
Option A: Incorrect. The C-O bond is polar (electronegativity of O > C).
Option B: Correct. For example, CO₂ has polar C=O bonds but is a nonpolar molecule due to its symm...