Which of the following molecules contains the least polar bond?

• A. HF
• B. H2O
• C. HCl
• D. H2

Answer: (D)

Verified step by step guidance

1. Identify the bonds present in each molecule: HF has an H-F bond, H2O has H-O bonds, HCl has an H-Cl bond, and H2 has an H-H bond.
2. Recall that bond polarity depends on the difference in electronegativity between the two atoms involved in the bond. The greater the difference, the more polar the bond.
3. Look up or recall the electronegativity values of the atoms: Hydrogen (H) ~2.1, Fluorine (F) ~4.0, Oxygen (O) ~3.5, Chlorine (Cl) ~3.0.
4. Calculate or compare the electronegativity differences for each bond: |2.1 - 4.0| for H-F, |2.1 - 3.5| for H-O, |2.1 - 3.0| for H-Cl, and |2.1 - 2.1| for H-H.
5. Determine which bond has the smallest electronegativity difference, indicating the least polar bond. The H-H bond in H2 has zero difference, so it is the least polar.