Final answer:
During World War I, Mustard Gas, Chlorine Gas, and Phosgene Gas were used as chemical weapons.
Step-by-step explanation:
During World War I, different types of gas were used, including Mustard Gas, Chlorine Gas, and Phosgene Gas. Mustard gas could burn the eyes, nose, and skin, causing permanent blindness and respiratory problems. Phosgene gas was colorless and could be deadly, with symptoms appearing after many hours. Chlorine gas, with its greenish hue, was one of the most common chemical weapons used by both sides in the war.