Question

Write equations for each of the above metal which reacts with water.

Answer 1

Being highly reactive, sodium is placed at the top of the reactivity series. It reacts violently with cold water forming sodium hydroxide and hydrogen gas; it may explode with hot water.

$$\begin{gathered} 2\mathrm{Na}+2{\mathrm{H}}_2\mathrm{O}\to 2\mathrm{NaOH}+{\mathrm{H}}_2 \\ \mathrm{Sodium}\mathrm{water}\mathrm{Sodium}\mathrm{Hydrogen}\mathrm{gas} \\ \mathrm{hydroxide} \end{gathered}$$

Calcium does not react violently with water and forms calcium hydroxide and hydrogen gas.

$$\begin{gathered} \mathrm{Ca}+2{\mathrm{H}}_2\mathrm{O}\stackrel{}{\to }\mathrm{Ca}(\mathrm{OH}{)}_2+{\mathrm{H}}_2 \\ \mathrm{Calcium}\mathrm{water}\mathrm{Calcium}\mathrm{hydroxide}\mathrm{Hydrogen}\mathrm{gas} \end{gathered}$$

Magnesium reacts very slowly with cold water but red hot magnesium reacts with steam to form magnesium oxide and hydrogen gas.

$$\begin{gathered} \mathrm{Mg}+{\mathrm{H}}_2\mathrm{O}\stackrel{}{\to }\mathrm{MgO}+{\mathrm{H}}_2 \\ \mathrm{Magnesium}\mathrm{Steam}\mathrm{Magnesium}\mathrm{oxide}\mathrm{Hydrogen}\mathrm{gas} \end{gathered}$$

Iron does not react with cold water but red hot iron reacts with steam to form tri-iron tetroxide and hydrogen. This is a reversible reaction.

$$\begin{gathered} 3\mathrm{Fe}+4{\mathrm{H}}_2\mathrm{O}\leftrightarrow {\mathrm{Fe}}_3{\mathrm{O}}_4+4{\mathrm{H}}_2 \\ \mathrm{Red}\mathrm{hot}\mathrm{Iron}\mathrm{Steam}\mathrm{Tri}\mathrm{i}\mathrm{ron}\mathrm{tetroxide}\mathrm{H}\mathrm{ydrogen}\mathrm{g}\mathrm{as} \end{gathered}$$