Question

Calcium reacts with cold water and forms Calcium hydroxide and Hydrogen gas.

• A. True
• B. False

Answer 1

The correct option is A True

The given statement is true.

• The highly reactive metals can react with cold water to form metal hydroxide and hydrogen gas$\left({\mathrm{H}}_2\right)$. Examples of such metals are Sodium$\left(\mathrm{Na}\right)$, Potassium$\left(\mathrm{K}\right)$ and Calcium$\left(\mathrm{Ca}\right)$.

$\mathrm{Ca}\left(\mathrm{s}\right)+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to \mathrm{Ca}{\left(\mathrm{OH}\right)}_2\left(\mathrm{aq}\right)+{\mathrm{H}}_2\left(\mathrm{g}\right)$

• While moderately reactive metals like Magnesium $\left(\mathrm{Mg}\right)$ react with hot water to produce metal hydroxide and hydrogen gas.

$\mathrm{Mg}\left(\mathrm{s}\right)+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to \mathrm{Mg}{\left(\mathrm{OH}\right)}_2\left(\mathrm{aq}\right)+{\mathrm{H}}_2\left(\mathrm{g}\right)$

• And the low reactive metals react with steam and form the metal oxide and hydrogen gas. Examples of such metals are

$\mathrm{Zn}\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)\to \mathrm{ZnO}\left(\mathrm{s}\right)+{\mathrm{H}}_2\left(\mathrm{g}\right)$