Calcium oxide, also known as quick lime, reacts vigorously with water to produce calcium hydroxide (slaked lime). This reaction, known as slaking, is a highly exothermic process, meaning that it releases a significant amount of heat.

The chemical equation for the reaction is:

$$CaO_{(s)} + H_2O_{(l)} → Ca(OH)_{2(s)}$$

The product, calcium hydroxide, is a white, powdery substance with a high pH, making it basic in nature. The heat produced during the slaking reaction can cause the water to boil and even produce steam, especially if a large amount of calcium oxide is used.

It is important to note that the reaction between calcium oxide and water is highly exothermic, so safety precautions should be taken when handling these substances, including wearing protective gear and avoiding direct contact with the reactants.