Which among the following changes are exothermic or endothermic in nature?
a) Decomposition of ferrous sulfate
b) Dilution of sulfuric acid
c) Dissolution of sodium hydroxide in water
d) Dissolution of ammonium chloride in water
Exothermic reactions:
During a reaction when if there is a release of energy in the form of heat or light then the reaction is classified as an exothermic reaction.
Endothermic reactions:
When a chemical reaction takes place, and heat is absorbed from the surroundings then the reaction is known as an endothermic reaction.
a) Decomposition of ferrous sulfate: The change is endothermic because the reaction absorbs heat during the decomposition of Ferrous sulfate (FeSO4).
b) Dilution of sulfuric acid: When Sulfuric acid (H2SO4) is dissolved in water, then the acid gets dissociated and release hydrogen ions and heat. Hence, the reaction is highly exothermic in nature.
c) Dissolution of sodium hydroxide in water: On dissolving sodium hydroxide (NaOH) in water, heat is evolved. Therefore, the change is an exothermic reaction.
d) Dissolution of ammonium chloride in water: Ammonium chloride (NH4Cl) when dissolved in water, then the temperature decreases due to absorption of heat. Therefore, the reaction is an endothermic reaction.