Ashok wanted his house white washed. He bought 10kg quick lime from market and dissolved it in 30 liters of water. On adding lime to water he noticed that bubbles were produced and the solution becomes hot. What was the product formed and why?

Quicklime reacts with water in an exothermic reaction. The product is slaked lime (calcium hydroxide).

The equation for the reaction is

CaO(s) + H₂O(l) ⇌ Ca(OH)₂(aq); ##ΔH_(rxn)## = −63.7 kJ/mol

The large amount of heat produced causes local boiling as the particles react. The steam bubbles are the water vapour that forms.