Question

Compare in tabular form the reactivities of the following metals with cold and hot water:

(a) Sodium (b) Calcium (c) Magnesium

Answer 1

Sodium	Calcium	Magnesium
The reaction of Sodium with cold water is very violent.	The reaction of calcium with cold water is less violent.	Magnesium does not react with cold water.
It is highly exothermic.	Calcium starts floating because the bubbles of hydrogen gas formed stick to the surface of the metal.	It reacts with hot water to form magnesium hydroxide.
It also reacts with hot water to form sodium hydroxide.	It also reacts with hot water and forms calcium hydroxide.	It also starts floating as the bubbles of Hydrogen gas stick to its surface.
$2\mathrm{Na}\left(\mathrm{s}\right)+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to 2\mathrm{NaOH}\left(\mathrm{aq}\right)+{\mathrm{H}}_2\left(\mathrm{g}\right)+\mathrm{Heat}$	$2\mathrm{Ca}\left(\mathrm{s}\right)+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to 2\mathrm{Ca}{\left(\mathrm{OH}\right)}_2\left(\mathrm{aq}\right)+{\mathrm{H}}_2\left(\mathrm{g}\right)$	$\mathrm{Mg}\left(\mathrm{s}\right)+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to \mathrm{Mg}{\left(\mathrm{OH}\right)}_2\left(\mathrm{aq}\right)+{\mathrm{H}}_2\left(\mathrm{g}\right)$