Which two observations will be made when quicklime is added to water? Mention two uses of the product obtained.

(N/A) Observations:
$(a)$ The reaction occurs vigorously.
$(b)$ $A$ large amount of heat is released (exothermic reaction).
Uses of the product $Ca(OH)_2$ (Calcium hydroxide):
$(a)$ It is used for whitewashing walls. It reacts slowly with $CO_2$ in the air to form a thin layer of calcium carbonate $(CaCO_3)$ on the walls,providing a shiny finish.
$(b)$ It is used as a laboratory reagent for testing the presence of $CO_2$ gas,as it turns milky upon reaction with it.