TRUE or FALSE: If the maximum adiabatic reaction temperature exceeds the reaction mixture boiling point, the reaction is capable of generating pressure in a closed vessel.

• A. False
• B. True
• C. Cannot determine
• D. Only with venting

Answer: (B)

When a reaction is run adiabatically, all the heat released goes into raising the temperature of the reacting mixture because no heat escapes. The highest temperature reached in this scenario is called the adiabatic temperature rise. If this maximum temperature is higher than the boiling point of the mixture, the liquid will begin to vaporize. In a closed vessel, the vapor cannot escape, so the formation of vapor builds up pressure. The key idea is that boiling can occur once the temperature exceeds the boiling point, and in a sealed system that vapor contributes to pressure rise, making a pressure hazard possible. Venting can mitigate this by releasing the vapor, but the potential for pressure generation exists regardless of venting.