Reaction of ick lime (CaO) with water to produce slaked lime (Ca(OH)2) is an example of

The reaction of quicklime (calcium oxide, CaO) with water to produce slaked lime (calcium hydroxide, Ca(OH)2) is a classic example of an exothermic reaction. During this process, calcium oxide reacts vigorously with water, releasing a significant amount of heat that makes the reaction mixture warm and can even produce steam [2]. In chemical terms, reactions that release heat into the surroundings are classified as exothermic. Additionally, this specific reaction is a combination reaction because two reactants (CaO and H2O) combine to form a single product, Ca(OH)2 [2]. It is not a displacement or decomposition reaction, as the latter would involve breaking down a compound into simpler substances, such as the thermal decomposition of limestone into quicklime [3]. Therefore, the evolution of heat confirms it is an exothermic reaction [1].

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 1: Chemical Reactions and Equations > Figure 1.3 > p. 6
2. [2] Science , class X (NCERT 2025 ed.) > Chapter 1: Chemical Reactions and Equations > QUESTIONS > p. 7
3. [3] https://www.sciencedirect.com/topics/engineering/lime-cycle