Why Is Heat Produced When We Add Water (H2O) To Calcium Oxide (Cao)?

Hi,

From literature :

CaO (s) + H2O (l)  --- >     Ca (OH) 2 (aq) (∆Hr = −63.7 kJ/mol of CaO)

exothermic reaction

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Breizh 

Edited by breizh, 01 January 2020 - 06:20 AM.

The elements Ca, O, H changed to a lower energy state giving that energy to the environment.  It became a more stable (lower energy) form.

This is the best and simplest explanation possible. Even a layman can understand that...!