Which of the following molecules contains a polar covalent bond?

A. CO
B. [tex]O_2[/tex]
C. [tex]H_2[/tex]
D. [tex]N_2[/tex]



Answer :

To determine which of the given molecules contains a polar covalent bond, we need to examine the electronegativity values of the atoms within these molecules. A polar covalent bond occurs when there is a difference in electronegativity between the two atoms bonded together, resulting in a partial positive charge on one atom and a partial negative charge on the other.

Here are the electronegativity values of the relevant atoms:
- Carbon (C): 2.55
- Oxygen (O): 3.44
- Hydrogen (H): 2.20
- Nitrogen (N): 3.04

Now let's analyze each molecule:

A. CO (Carbon Monoxide)
- In CO, Carbon (C) has an electronegativity of 2.55, and Oxygen (O) has an electronegativity of 3.44.
- The difference in electronegativity is [tex]\( |3.44 - 2.55| = 0.89 \)[/tex].
- Since the difference of 0.89 falls within the range for a polar covalent bond (typically between 0.4 and 1.7), CO contains a polar covalent bond.

B. [tex]\(O_2\)[/tex] (Oxygen Molecule)
- In [tex]\(O_2\)[/tex], both atoms are Oxygen (O) with an electronegativity of 3.44.
- The difference in electronegativity is [tex]\( |3.44 - 3.44| = 0 \)[/tex].
- With no difference in electronegativity, [tex]\(O_2\)[/tex] contains a nonpolar covalent bond.

C. [tex]\(H_2\)[/tex] (Hydrogen Molecule)
- In [tex]\(H_2\)[/tex], both atoms are Hydrogen (H) with an electronegativity of 2.20.
- The difference in electronegativity is [tex]\( |2.20 - 2.20| = 0 \)[/tex].
- With no difference in electronegativity, [tex]\(H_2\)[/tex] contains a nonpolar covalent bond.

D. [tex]\(N_2\)[/tex] (Nitrogen Molecule)
- In [tex]\(N_2\)[/tex], both atoms are Nitrogen (N) with an electronegativity of 3.04.
- The difference in electronegativity is [tex]\( |3.04 - 3.04| = 0 \)[/tex].
- With no difference in electronegativity, [tex]\(N_2\)[/tex] contains a nonpolar covalent bond.

Based on the analysis, the correct answer is:
A. CO