Question

explan the similarity and different in two event namely adding NaOH to water and adding CaO to water

Answer 1

Similarly between them is that they both react easily and vigorously when added to water at normal' temperature only....
The main difference between them is that NaOH gets dissociated into Na+ ions and OH- ions, while in case of CaO it reacts to form Calcium hydroxide compound Ca(OH)2