CaO is expected to react with sodium hydroxide (NaOH) to form calcium hydroxide [Ca(OH)2] and sodium oxide (Na2O). The reaction can be represented as:

CaO + 2NaOH → Ca(OH)2 + Na2O

This reaction occurs because CaO is a basic oxide, while NaOH is a strong base. When these two compounds come into contact with each other, they undergo a chemical reaction to form the corresponding products. The reaction is exothermic, meaning that it releases heat.

The products of this reaction, Ca(OH)2 and Na2O, are both white solids. Calcium hydroxide is a common ingredient in cement, while sodium oxide is used in the production of glass and ceramics.