Final answer:
Cyanuric triazide is classed as a dangerously reactive material due to its potential for strong and violent chemical reactions. Density and pH are examples of physical properties, while corrosiveness and flammability fall under chemical properties.
Step-by-step explanation:
Cyanuric triazide is a dangerously reactive material. When considering the options, reactive flammable materials are generally those that can ignite easily and sustain combustion. Corrosive substances lead to the deterioration or destruction of other materials by chemical reaction. Combustible liquids have a flash point at or above 37.8°C (100°F) and below 93.3°C (200°F). Dangerously reactive materials, on the other hand, are substances that can undergo strong and sometimes violent chemical reactions when exposed to normal handling or environmental conditions.
Exercise 3.5.1 A relates to this question as it distinguishes between physical and chemical properties of matter. Density and pH are examples of physical properties, whereas corrosiveness and flammability are defined as chemical properties.