An active metal reacting with water produces an oxide or hydroxide and hydrogen gas.
Active Metal is a collective name for metals that react strongly or quickly with other substances. The very active metals react with water. For example, calcium reacts with water to form calcium hydroxide and hydrogen gas. Calcium metal has an oxidation number of 0, whereas Ca 2+ in Ca(OH)2 has an oxidation number of +2, so calcium is oxidized. Hydrogen’s oxidation number changes from +1 to 0, so it is reduced.
Ca (s) + 2H2O ( l ) → Ca(OH)2 (aq) + H2 (g)