Which of the following chemical reactions takes place when quick lime reacts with water?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. CaO(s) + H2O(l) → Ca(OH)2(aq).
When quick lime (calcium oxide, CaO) reacts with water, it forms slaked lime (calcium hydroxide, Ca(OH2)) in an exothermic reaction, releasing a significant amount of heat. This reaction is commonly used in construction for making lime mortar and in agriculture to neutralize acidic soils.
The product, slaked lime, dissolves slightly in water to produce an alkaline solution, also known as lime water. This is a classic example of a hydration reaction.