The correct answer is option 2, Sodium azide. Airbags, used for the safety of car drivers, contain Sodium azide. This is a chemical compound that is commonly used as a propellant in airbags. When a car experiences a sudden impact, a sensor detects the rapid deceleration and triggers the inflation system of the airbag. Sodium azide is then rapidly ignited, decomposing into nitrogen gas and sodium metal. The nitrogen gas fills up the airbag, inflating it quickly to provide cushioning and protection for the driver during a crash. The chemical reaction that occurs is highly exothermic, meaning it releases a large amount of energy in the form of heat. This rapid deployment of the airbag helps to prevent or minimize injuries to the driver by absorbing some of the impact force during a collision. It should be noted that Sodium azide is a toxic substance and should be handled with caution.