Multiple choice What is the molecular formula of pentane? C2H6 C3H8 C4H10 C5H12 Reveal answer Fill a bubble to check yourself D Correct answer Explanation Pentane is a 5-carbon alkane, and all alkanes follow the formula CnH2n+2. For n=5, this gives C5H12. The other options represent ethane, propane, and butane respectively.