Answer: Option (2) is the correct answer.
Explanation:
A chemical reaction in which reactants absorb energy is known as an endothermic reaction. Also, in this reaction energy of reactants is less than the energy of products.
For example, when ammonium chloride is dissolved in water then the solution becomes cold as the reaction is endothermic in nature.
Whereas a chemical reaction in which energy is released is known as exothermic reaction. Also, in this type of reactions energy of reactants is more than the energy of products.
For example, when NaOH is dissolve in water then heat is released as it dissociates into sodium and hydroxide ions. Further, product formed that is, species sodium and hydroxide ions acquire low energy state. Hence, the reaction is exothermic in nature.
Thus, we can conclude that NaOH is the compound in which process of dissolving in water is exothermic.
