Hydrocarbon Properties and Petroleum Basics

Steps:

• Evaluate A: Check definition of hydrocarbons—must contain only C and H.
• Evaluate B: Recall petroleum is a mixture, not a single compound.
• Evaluate C: Consider trend in boiling points with increasing chain length due to molecular size.
• Evaluate D: Identify uses of naphtha fraction versus road-making materials like bitumen.

Why C is correct:

• Longer hydrocarbon chains have greater surface area, increasing van der Waals forces and thus requiring more energy to boil, per intermolecular force principles.

Why the others are wrong:

• A: Hydrocarbons contain only C and H; compounds with C, H, and other elements (e.g., alcohols) are not hydrocarbons.
• B: Petroleum is a complex mixture of hydrocarbons, not a single compound.
• D: Naphtha is used for petrochemicals like plastics; roads use asphalt from heavier fractions.

Final answer: C