Q. Consider the following hydrocarbons related to their boiling points:

1. Methane
2. Ethane
3. Propane
4. Butane

Which of the following correctly arranges them in order of increasing boiling point?
Answer: 1 < 2 < 3 < 4
Notes: Boiling point in alkanes increases with molecular mass and chain length due to stronger van der Waals forces. Thus, among methane, ethane, propane, and butane, the correct order from lowest to highest boiling point is: methane < ethane < propane < butane, that is, 1 < 2 < 3 < 4.