Gay Lussac’s Law of Combining Volumes:
This law states that the volume of gases taking part in a chemical reaction show simple whole number ratio to. one another when those volumes are measured at the same temperature and pressure.
For the reactions:
1 volume of nitrogen combines with 3 volumes of hydrogen to form 2 volumes of ammonia.
2 volumes of hydrogen combine with 1 volume of oxygen to form 2 volumes of steam.