What are the three types of choking agents?

The three types of choking agents are correctly identified as Phosgene, Diphosgene, and Chlorine. These substances are classified as choking agents because they primarily affect the respiratory system, leading to difficulty in breathing and other related symptoms.

Phosgene is a highly toxic gas that can cause lung damage and respiratory failure. It was used extensively in World War I and is known for its insidious effects, which may not be immediately apparent to those exposed. Diphosgene is a compound that is structurally similar to Phosgene and exhibits similar toxic effects. Chlorine, while primarily known as a disinfectant, can also serve as a choking agent when released in large quantities, leading to respiratory distress.

In summary, these agents are grouped together due to their chemical properties and their impact on human respiratory health, making this answer the most accurate choice related to choking agents.