The substance with the highest boiling point among the options given is:
- water
Water (H₂O) has a boiling point of 100°C (212°F) at standard atmospheric pressure, which is higher than the boiling points of ammonia (NH₃), nitrogen (N₂), and hydrogen sulfide (H₂S).
- Ammonia: -33.34°C
- Nitrogen: -195.79°C
- Hydrogen sulfide: -60.2°C
Therefore, the correct answer is 1. water.