why on adding lime to water it starts boiling?Does the amount of water or lime have any effect on the intensity of the reaction?FOR EG:-IF 10 kg of lime is dissolved in 30 litres of water.What if 5kg of lime is added to 30 ltrs of water?

Calcium is a chemical compound and its molecular formula is CaO. Calcium oxide is also called quick lime. When calcium oxide reacts with water calcium hydroxide is formed. 

Calcium hydroxide is also called slaked lime or hydrated lime. This reaction is an exothermic reaction because a large amount of heat is evolved during this chemical reaction.

CaO (s) + H₂O (l)  Ca(OH)₂ (aq) (ΔH_r = −63.7 kJ/mol of CaO)

As the reaction is exothermic  (energy is given out) and energy released during the reaction is sufficient to boil water.

According to the reaction, CaO is limiting reagent and we know that the reaction will always carry out according to the limiting reagent.Hence, the amount of calcium oxide will definitely make impact on the reaction but there will not be any effect of water on this reaction as water is the excess reagent in the given reaction.