Question

List the chemical properties of carbon dioxide.

Answer 1

Chemical properties of carbon dioxide:

Carbon dioxide (${\mathbf{CO}}_{\mathbf{2}}$) , a gas composed of two oxygen atoms and one carbon atom is a chemically reactive gas. It exhibits various chemical properties which are as follows:

• Combustion: Carbon dioxide being a non-combustible gas does not favour combustion. But some of the metals like potassium and magnesium burn in carbon dioxide because the oxygen atom present in carbon dioxide has the ability to bond with potassium and magnesium and form their respective oxides along with the production of black specks of carbon. The reaction to this is given as;

$\underset{\mathbf{Potassium}}{\mathbf{4}\mathbf{K}\mathbf{\left(}\mathbf{s}\mathbf{\right)}}\mathbf{}\mathbf{+}\mathbf{}\underset{\mathbf{Carbon}\mathbf{}\mathbf{dioxide}}{{\mathbf{CO}}_{\mathbf{2}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}}\mathbf{\to }\underset{\mathbf{Potassium}\mathbf{}\mathbf{oxide}}{\mathbf{2}{\mathbf{K}}_{\mathbf{2}}\mathbf{O}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{}}\mathbf{+}\mathbf{}\underset{\mathbf{Carbon}\mathbf{}\mathbf{(}\mathbf{black}\mathbf{}\mathbf{specks}\mathbf{)}}{\mathbf{C}\mathbf{\left(}\mathbf{s}\mathbf{\right)}}$

$\underset{\mathbf{Magnesium}}{\mathbf{2}\mathbf{Mg}\mathbf{\left(}\mathbf{s}\mathbf{\right)}}\mathbf{}\mathbf{+}\mathbf{}\underset{\mathbf{Carbon}\mathbf{}\mathbf{dioxide}}{{\mathbf{CO}}_{\mathbf{2}}\mathbf{(}\mathbf{g}}\mathbf{)}\mathbf{}\mathbf{\to }\mathbf{}\underset{\mathbf{Magnesium}\mathbf{}\mathbf{oxide}}{\mathbf{2}\mathbf{MgO}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{}}\mathbf{+}\mathbf{}\underset{\mathbf{Carbon}\mathbf{(}\mathbf{black}\mathbf{}\mathbf{specks}\mathbf{)}}{\mathbf{C}\mathbf{\left(}\mathbf{s}\mathbf{\right)}}$

• Reaction with lime water: Lime water is basically a solution of calcium hydroxide ($\mathbf{Ca}{\mathbf{\left(}\mathbf{OH}\mathbf{\right)}}_{\mathbf{2}}$). When carbon dioxide is bubbled through limewater, a white precipitate of calcium carbonate (${\mathbf{CaCO}}_{\mathbf{3}}$) is formed which turns the limewater milky or cloudy white. The reaction is given below;

$\underset{\underset{\mathbf{(}\mathbf{Lime}\mathbf{}\mathbf{water}\mathbf{)}}{\mathbf{Calcium}\mathbf{}\mathbf{hydroxide}}}{\mathbf{Ca}{\mathbf{\left(}\mathbf{OH}\mathbf{\right)}}_{\mathbf{2}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}}\mathbf{}\mathbf{+}\mathbf{}\underset{\mathbf{Carbon}\mathbf{}\mathbf{dioxide}}{{\mathbf{CO}}_{\mathbf{2}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}}\mathbf{}\mathbf{\to }\underset{\underset{\underset{\mathbf{(}\mathbf{turns}\mathbf{}\mathbf{lime}\mathbf{}\mathbf{water}\mathbf{}\mathbf{milky}\mathbf{)}}{\mathbf{(}\mathbf{white}\mathbf{}\mathbf{ppt}\mathbf{.}\mathbf{)}}}{\mathbf{Calcium}\mathbf{}\mathbf{carbonate}}}{\mathbf{}{\mathbf{CaCO}}_{\mathbf{3}}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{}}\mathbf{+}\mathbf{}\underset{\mathbf{Water}}{{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\mathbf{\left(}\mathbf{l}\mathbf{\right)}}$

When carbon dioxide is bubbled in excess through the solution for extended period of time, calcium hydrogen carbonate ($\mathbf{Ca}{\mathbf{\left(}{\mathbf{HCO}}_{\mathbf{3}}\mathbf{\right)}}_{\mathbf{2}}$) is formed which is soluble in water. Hence, the turbidity of solution disappears and the solution becomes clear. The reaction for the same is given below;

• Reaction with bases: Carbon dioxide being acidic in nature when reacts with bases results in the formation of salts and water. The salt formed here is in the form of carbonates. When further subjected to react with more carbon dioxide, the corresponding bicarbonates are formed. The reaction is given as;

$\underset{\mathbf{Sodium}\mathbf{}\mathbf{hydroxide}}{\mathbf{2}\mathbf{NaOH}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{}}\mathbf{+}\underset{\mathbf{Carbon}\mathbf{}\mathbf{dioxide}}{\mathbf{}{\mathbf{CO}}_{\mathbf{2}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}}\mathbf{}\mathbf{\to }\underset{\mathbf{Sodium}\mathbf{}\mathbf{carbonate}}{\mathbf{}{\mathbf{Na}}_{\mathbf{2}}{\mathbf{CO}}_{\mathbf{3}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}}\mathbf{}\mathbf{+}\underset{\mathbf{Water}\mathbf{}}{\mathbf{}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\mathbf{\left(}\mathbf{l}\mathbf{\right)}}$

$\underset{\mathbf{Sodium}\mathbf{}\mathbf{carbonate}}{{\mathbf{Na}}_{\mathbf{2}}{\mathbf{CO}}_{\mathbf{3}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}}\mathbf{}\mathbf{+}\underset{\mathbf{Carbon}\mathbf{}\mathbf{dioxide}}{\mathbf{}{\mathbf{CO}}_{\mathbf{2}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}}\mathbf{}\mathbf{+}\mathbf{}\underset{\mathbf{Water}}{{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\mathbf{\left(}\mathbf{l}\mathbf{\right)}}\mathbf{}\mathbf{\to }\mathbf{}\underset{\mathbf{Sodium}\mathbf{}\mathbf{bicarbonate}}{\mathbf{2}{\mathbf{NaHCO}}_{\mathbf{3}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}}$

• Reaction with water: When carbon dioxide is dissolved in water, an acidic solution is obtained. This is due to the formation of carbonic acid which is a weak acid. The reaction is given as;

$\underset{\mathbf{Water}}{{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\mathbf{\left(}\mathbf{l}\mathbf{\right)}}\mathbf{}\mathbf{+}\mathbf{}\underset{\mathbf{Carbon}\mathbf{}\mathbf{dioxide}}{{\mathbf{CO}}_{\mathbf{2}}\mathbf{(}\mathbf{g}}\mathbf{)}\mathbf{}\mathbf{\to }\underset{\underset{\mathbf{(}\mathbf{Weak}\mathbf{}\mathbf{acid}\mathbf{)}}{\mathbf{Carbonic}\mathbf{}\mathbf{acid}}}{\mathbf{}{\mathbf{H}}_{\mathbf{2}}{\mathbf{CO}}_{\mathbf{3}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}}$

• Reaction of carbon dioxide with litmus solution/paper: When a blue litmus paper is dipped into the solution of carbon dioxide it turns the blue litmus paper into red. This is because the solution of carbon dioxide is acidic.