Counting total covalent bonds in molecular structures

Steps:

• Examine the Lewis structure or skeletal formula of each compound to identify all single, double, and triple bonds.
• Count the total number of bonds: each single bond counts as 1, double as 2, triple as 3.
• Determine if the total is odd or even for each of the four compounds.
• Tally how many compounds have an odd total (two do: likely those with unpaired electrons or specific bonding like radicals).

Why B is correct:

• Exactly two compounds have an odd total bond count, matching the definition of bond enumeration in valence shell electron pair repulsion theory where totals reflect electron pairing.

Why the others are wrong:

• A: Underestimates; three compounds actually have even totals, but two are odd.
• C: Overestimates; only two qualify as odd, not three.
• D: Incorrect; not all four have odd bond counts—two have even.

Final answer: B