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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.
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Solution
- Chemical equations involved:
- \[\ce{NaOH(s)+H2O(l) -> {Na}^+_{(aq)} + OH^-_{(aq)} + \triangle (HEAT)}\]
- \[\ce{CaO(s) + H2O(l) -> Ca(OH)2(aq) + \triangle(HEAT)}\]
- Similarities:
- Both of the equations are exothermic. It means a lot of heat is evolved during the reaction.
- Both reactions form strong basic solutions
- Differences:
- 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.
- NaOH is a monoacidic base. and CaO is a diacidic base.
- 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.
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