Question

Is there evolution of heat when cao reacts with h2o?

Answer 1

Yes heat is evolved when CaO reacts with H2O

CaO+H2O=Ca(OH)2+ heat

This is exothermic reaction

Hope it helps you

Answer 2

cao +h2o-----≥ca(oh)2

these mixture are added to water to lime(cao)

and heat the evolution of the energy as a heat is evidence because of the mixture become warm and these reaction are exothermic