Sodium reacts vigorously with water to form sodium hydroxide (NaOH) and hydrogen gas (H2). The reaction can be represented as:

2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)

This reaction is highly exothermic, releasing a significant amount of heat. The hydrogen gas produced is flammable and can ignite spontaneously in the presence of an ignition source. Therefore, caution must be exercised when handling sodium and water.