The correct option is Endothermic reactions.
Explanation
Chemical reactions involve the breaking and making of bonds, which is accompanied by energy changes. Based on the heat exchange between the system and the surroundings, reactions are broadly classified into exothermic and endothermic types.
Option Analysis:
- Endothermic reactions is correct: Endothermic reactions are chemical reactions that absorb energy (usually in the form of heat) from the surroundings. In these reactions, the energy required to break bonds in the reactants is greater than the energy released when new bonds form in the products. Consequently, the temperature of the surroundings typically decreases.
- Exergonic reactions is incorrect: Exergonic reactions refer to reactions where the change in Gibbs free energy is negative, meaning they release free energy and occur spontaneously. The counterpart term for energy absorption in this context is endergonic.
- Catalytic reactions is incorrect: Catalytic reactions are defined by the presence of a catalyst, which speeds up the reaction rate by lowering activation energy. A catalytic reaction can be either exothermic or endothermic depending on the net energy change.
- Neutralisation reactions is incorrect: Neutralisation reactions involve the reaction between an acid and a base to form salt and water. These reactions are characteristically exothermic, meaning they release heat.
Key Takeaway: Endothermic reactions absorb heat ($\Delta H > 0$), whereas exothermic reactions release heat ($\Delta H < 0$) into the surroundings.