Molecular formulas differ for ethyne and benzene Steps:

• Identify molecular formula of ethyne as C₂H₂.
• Identify molecular formula of benzene as C₆H₆.
• Compare the two molecular formulas: C₂H₂ ≠ C₆H₆.
• Conclude that statement B accurately describes this difference.

Why B is correct:

• By definition, the molecular formula gives the exact atom composition of one molecule, so ethyne's C₂H₂ and benzene's C₆H₆ are distinct for these different compounds.

Why the others are wrong:

• A: Empirical formula is CH for both ethyne and benzene, differing from their respective molecular formulas C₂H₂ and C₆H₆.
• C: This is a general definition of empirical formula but does not address the specific formulae of ethyne and benzene.
• D: This is a general definition of molecular formula but does not address whether those of ethyne and benzene are the same or different.

Final answer: B