Which aliphatic compound is characterized by the formula C5H12?

The answer is pentane, which has the chemical formula C5H12. This formula indicates that pentane consists of five carbon atoms and twelve hydrogen atoms, which fits the structure of aliphatic hydrocarbons known as alkanes. Alkanes are saturated hydrocarbons, meaning they contain only single bonds between carbon atoms. In the case of pentane, it can be arranged in different structural forms, including straight-chain and branched isomers, but all variations still conform to the C5H12 formula.

Understanding the structure provides insight into how pentane functions and its physical properties, such as its state at room temperature and its reactivity. The other compounds listed (heptane, butane, and propane) have different carbon counts and, consequently, different formulas. Heptane has seven carbon atoms (C7H16), butane has four (C4H10), and propane has three (C3H8). Thus, only pentane is consistent with the given molecular formula C5H12.