A reaction that cools the surroundings is described as

• A. Endothermic
• B. Exothermic
• C. Isothermal
• D. Adiabatic

Answer: (A)

When heat is taken from the surroundings into the reacting system, the surroundings cool down. This shows the reaction is absorbing energy, which is the hallmark of an endothermic process. In endothermic reactions, energy enters the system (positive heat change for the system), so the surroundings lose heat and get cooler.

This differs from exothermic reactions, which release heat to the surroundings and make them warmer. Isothermal would mean the temperature stays the same, so there isn’t a cooling of the surroundings. Adiabatic means no heat exchange with the surroundings, so you wouldn’t expect the surroundings to cool due to heat transfer from the reaction.