Question

Write the answer to the following.

Explain the similarity and difference in two events, namely adding NaOH to water and adding CaO to water.

Answer 1

1. Chemical equations involved:
   1. \[\ce{NaOH(s)+H2O(l) -> {Na}^+_{(aq)} + OH^-_{(aq)} + \triangle (HEAT)}\]
   2. \[\ce{CaO(s) + H2O(l) -> Ca(OH)2(aq) + \triangle(HEAT)}\]
2. Similarities:
   1. Both of the equations are exothermic. It means a lot of heat is evolved during the reaction.
   2. Both reactions form strong basic solutions
3.  Differences:
   1. Sodium Hydroxide is a strong base that dissociates to form Na⁺ and OH⁻ ions While Calcium oxide adds water to form Calcium Hydroxide which further dissociates.
   2. NaOH is a monoacidic base. and CaO is a diacidic base.
   3.  NaOH and CaO should be added to water gradually with constant stirring. CaO, on reacting with water, produces a basic solution called Calcium hydroxide which is used for whitewashing and this reaction is more dangerous as compared to NaOH.