Which of the following Lewis electron-dot diagrams represents the molecule that is the most polar?

• A. H--C--H (methane)
• B. Cl--Cl (chlorine gas)
• C. H--O--H (water)
• D. O=C=O (carbon dioxide)

Answer: (C)

Verified step by step guidance

1. Step 1: Understand that molecular polarity depends on both the polarity of individual bonds and the overall shape (geometry) of the molecule, which affects how bond dipoles add up.
2. Step 2: Analyze each molecule's Lewis structure to determine the arrangement of atoms and the presence of lone pairs, which influence molecular shape.
3. Step 3: Identify the electronegativity differences between bonded atoms to assess bond polarity. For example, O-H bonds are polar because oxygen is more electronegative than hydrogen.
4. Step 4: Consider the molecular geometry: methane (CH\_4) is tetrahedral and symmetrical, chlorine gas (Cl\_2) is diatomic and nonpolar, carbon dioxide (CO\_2) is linear and symmetrical, and water (H\_2O) is bent due to lone pairs on oxygen, leading to an overall dipole moment.
5. Step 5: Conclude that the molecule with the bent shape and polar bonds (H\_2O) has an uneven distribution of charge, making it the most polar among the options.