Which of the following bonds is considered a polar covalent bond?

• A. Na–Cl
• B. H–Cl
• C. Cl–Cl
• D. C–C

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the concept of bond polarity. A polar covalent bond occurs when two atoms share electrons unequally due to a difference in electronegativity between them.
2. Step 2: Recall that electronegativity is a measure of an atom's ability to attract shared electrons in a bond. The greater the difference in electronegativity between two atoms, the more polar the bond.
3. Step 3: Analyze each bond option by comparing the electronegativities of the atoms involved: Na–Cl, H–Cl, Cl–Cl, and C–C.
4. Step 4: Recognize that Na–Cl is an ionic bond because sodium (Na) is a metal and chlorine (Cl) is a nonmetal with a large electronegativity difference, leading to electron transfer rather than sharing.
5. Step 5: Identify that Cl–Cl and C–C bonds are nonpolar covalent bonds because the atoms are identical, so electrons are shared equally. The H–Cl bond has a moderate electronegativity difference, resulting in unequal sharing of electrons, which makes it a polar covalent bond.