The given blank can be filled with endothermic reactions.
The endothermic reactions or processes captivates energy from its surroundings, primarily, but will not always be in the form of heat. A reaction, which requires the input of energy that dissociates a bond will always be endothermic. The best examples of endothermic reactions are evaporation of the liquid, melting cubes, melting or solid salts, and others.
Endothermic reaction takes place when heat is absorbed from the surrounding. Exothermic reaction takes place when heat is released into the surrounding. Catalyzed reaction takes place only in the presence of a catalyst. The role of a catalyst is to lower the activation of a reaction and accelerates the rate of the reaction. In a combustion reaction hydrocarbon in the presence of oxygen produces carbon dioxide and water.
As endothermic reaction requires high heat to start the process is nonspontaneous.
