AEMCA Practice Exam

What characterizes phosgene?

1. A colorless, flammable gas

2. A colorless, nonflammable gas that is a pulmonary toxic agent

3. A yellow gas used in riot control

4. A solid chemical used for industrial purposes

The correct answer is: A colorless, nonflammable gas that is a pulmonary toxic agent

Phosgene is characterized as a colorless, nonflammable gas that serves as a pulmonary toxic agent. This means that while it is not visible to the naked eye in its gaseous state, it poses serious health risks due to its toxicity when inhaled. Phosgene has a history of being used as a chemical warfare agent due to its ability to damage lung tissue, making it particularly dangerous, even in relatively low concentrations. Its nonflammability is significant in differentiating it from other toxic gases, which may have flammable properties. In understanding the other options, it's notable that phosgene is not a flammable gas, which invalidates the first choice. Additionally, it is not a yellow gas, nor is it used for riot control; those descriptions could refer to other chemicals, such as tear gas. Finally, phosgene is not a solid chemical; it exists as a gas at room temperature and is commonly encountered in vapor form. This specificity in characteristics helps to reinforce why the assertion that it is a colorless, nonflammable gas that acts as a pulmonary toxic agent is accurate and critical for understanding the risks it poses.