Final answer:
Water has high melting and boiling points due to hydrogen bonding and strong intermolecular interactions.
Step-by-step explanation:
Water has unusually high melting and boiling points (0°C and 100°C, respectively) for such a small molecule. The boiling points for similar-sized molecules, such as methane (BP = -162°C) and ammonia (BP = −33°C), are more than 100° lower. This is because water molecules experience a relatively strong intermolecular interaction known as hydrogen bonding. Hydrogen bonds result in a large amount of energy required to break apart the bonded network of water molecules, allowing them to maintain a liquid phase at higher temperatures than expected.