Answer: Endothermic
Step-by-step explanation:
An endothermic reaction occurs when energy is absorbed as heat, while a reaction is exothermic when heat is released. Thereby, these type of reactions require external energy to proceed and heat is the reactant.
So, an endothermic reaction absorbs heat from the surrounding environment and stores that energy in the bonds of a new molecule formed, and this results in a decrease in temperature.
Enthalpy usually increases in endothermic reactions. However, a spontaneous endothermic reaction can occur if changes in entropy and enthalpy yield a negative Gibbs free energy.