Which hydrocarbon would have the highest boiling point?

The hydrocarbon with the highest boiling point among the given options is the one represented by the formula H-C-C-C-C-C-C-C-H, which indicates a long-chain alkane. As the number of carbon atoms in a hydrocarbon increases, the boiling point typically increases due to a greater surface area and stronger van der Waals forces (dispersion forces) between the molecules.

In this case, the long-chain hydrocarbon has significantly more carbon atoms compared to the others listed. This substantial increase in molecular size leads to a larger molecular surface area, allowing for more effective temporary dipole interactions, which translate to higher boiling points.

In contrast, the other options represent shorter alkane chains. Ethane (C2H6), propane (C3H8), and butane (C4H10) all have fewer carbon atoms and, consequently, lower boiling points due to weaker intermolecular forces, making them less capable of requiring the energy needed to overcome those forces during boiling. Thus, the long-chain hydrocarbon will have the highest boiling point due to its increased size and the resultant increase in intermolecular attraction.