Place the metals calcium, iron, magnesium and sodium in order of their activity with water, placing the most active first. Write the equation for each of the above metals which react with Water.

These metals arranged in order of their activity with water:

Na > Ca > Mg > Fe

Equations for reaction of metals with water:

Sodium

$2\text{Na} + \underset{\text{cold water}}{2\text{H}$2\text{O}} \longrightarrow 2\text{NaOH} + \text{H}2

Calcium

$\text{Ca} + \underset{\text{cold water}}{2\text{H}$2\text{O}} \longrightarrow \text{Ca(OH)}2 + \text{H}_2

Magnesium

$\text{Mg} + \underset{\text{boiling water}}{\text{H}$2\text{O}} \longrightarrow \text{MgO} + \text{H}2

Iron

$3\text{Fe} + \underset{\text{[steam]}}{4\text{H}$2\text{O}} \rightleftharpoons \underset{\text{[magnetic oxide of iron]}}{\text{Fe}3\text{O}4} + 4\text{H}2