Explanation:
The main difference in boiling points are due to intermolecular attractions. With water, it is a polar molecule, has hydrogen bonding, and exhibits london forces. All of these combined, make H2O bonds very strong, which means more energy is required to transition from one state to another, leading to higher boiling points.
On the other hand, methane is a non-polar molecule that only exhibits very weak london forces. It being a non-polar molecule, means its bonds are very weak, which means less energy is required to boil methane.
Also, the Celsius system was made so that water would be a reference. This is a reason for why its boiling point temperature is convenient
