Question

Addition of water to calcium oxide, is an example of
both
(1) Combination and endothermic reaction
(2) Combination and exothermic reaction
(3) Decomposition and endothermic reaction
(4) Decomposition and exothermic reaction

Answer 1

2) combination and exothermic reaction

Answer 2

The answer is 2)Combination and exothermic reaction.

When water is added to CaO, the reaction produces large amount of heat and forms Calcium hydroxide or Ca(OH)2. This is a combination reaction