Answer:
CO contains a polar bond.
Step-by-step explanation:
CO has a polar bond because of the electronegativity difference between the C and O atom. According to Pauling scale the electronegativity value of C and O are 2.5 and 3.5 respectively. So the electronegativity difference in C-O bond is (3.5 – 2.5)1.0, which greater than 0.5 and hence polar.
O₂, N₂ and H₂ do not have polar bonds as there is no electronegativity difference between two atoms of the same element.