Question

Based on the given experimental set-up showing reaction of quick lime ( $\text{CaO}$ ) with water:

(a) Identify the type of reaction taking place and mention why does the beaker become hot. (b) Write the balanced chemical equation.

Experimental set-up showing quick lime reacting with water in a beaker, with a hand touching the beaker indicating heat generation

Accepted Answer

(a) **Type of reaction:** Combination reaction (and Exothermic reaction). **Reason for heat:** Quick lime reacts vigorously with water to form slaked lime, releasing a large amount of heat energy. (b) **Balanced chemical equation:** $$	ext{CaO}(s) + 	ext{H}_2	ext{O}(l) ightarrow 	ext{Ca(OH)}_2(aq) + 	ext{Heat}$$

Reaction of Quicklime with Water

Explanation

Practise this under board exam conditions