Which alkane has seven carbon atoms?

• A. Hexane
• B. Heptane
• C. Octane
• D. Pentane

Answer: (B)

This tests your ability to name alkanes by the number of carbon atoms. Alkanes are saturated hydrocarbons with the formula CnH2n+2, and their names use prefixes that indicate how many carbons: pent- for five, hex- for six, hept- for seven, oct- for eight, each ending with the suffix -ane. For seven carbons, the name is heptane (C7H16). The other options correspond to five, six, and eight carbons respectively (pentane, hexane, octane).