When calcium metal reacts with water, it undergoes a chemical reaction called hydrolysis to produce calcium hydroxide [Ca(OH)2] and hydrogen gas [H2]. Calcium hydroxide is a strong base and is commonly known as slaked lime, while hydrogen gas is a colorless, odorless, and highly flammable diatomic gas. The reaction between calcium and water can be represented as follows: Ca (s) + 2H2O (l) → Ca(OH)2 (aq) + H2 (g).