Question

Classify the solutions of the following as acids, bases or salts:

Ammonium hydroxide, Barium chloride, Sodium chloride, Sodium hydroxide, ${\mathrm{H}}_2{\mathrm{SO}}_4$ and ${\mathrm{HNO}}_3$.

Answer 1

Acids:

• An acid is a substance in which the only positive ion is hydrogen.
• Sulfuric acid $\mathrm{\left(}{\mathrm{H}}_{\mathrm{2}}{\mathrm{SO}}_{\mathrm{4}}\left(\mathrm{aq}\right)\mathrm{\right)}$ and Nitric acid $\mathrm{\left(}{\mathrm{HNO}}_{\mathrm{3}}\left(\mathrm{aq}\right)\mathrm{\right)}$ are acids.
• When Sulfuric acid and nitric acid dissociate, they give hydrogen ions $\mathrm{\left(}{\mathrm{H}}^{\mathrm{+}}\mathrm{\left(}\mathrm{aq}\mathrm{\right)}\mathrm{\right)}$.
• The chemical reactions are as follows:

${\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)\rightleftharpoons 2{\mathrm{H}}^{+}\left(\mathrm{aq}\right)+{\mathrm{SO}}_4^{-}\left(\mathrm{aq}\right)$

${\mathrm{HNO}}_3\left(\mathrm{aq}\right)\rightleftharpoons {\mathrm{H}}^{+}\left(\mathrm{aq}\right)+{\mathrm{NO}}_3^{-}\left(\mathrm{aq}\right)$

Base:

• Oxides or hydroxides of metals that react with the acid to form salts and water are called bases.
• Base dissociates completely to give Hydroxide ions $\mathrm{\left(}{\mathrm{OH}}^{\mathrm{-}}\mathrm{\left(}\mathrm{aq}\mathrm{\right)}\mathrm{\right)}$ in the aqueous solution.
• Ammonium hydroxide $\mathrm{\left(}{\mathrm{NH}}_{\mathrm{4}}\mathrm{OH}\left(\mathrm{aq}\right)\mathrm{\right)}$ and Sodium hydroxide $\mathrm{\left(}\mathrm{NaOH}\left(\mathrm{aq}\right)\mathrm{\right)}$ are the bases.
• When ammonium hydroxide and sodium hydroxide dissociate, they give hydroxide ions $\mathrm{\left(}{\mathrm{OH}}^{\mathrm{-}}\mathrm{\left(}\mathrm{aq}\mathrm{\right)}\mathrm{\right)}$.
• The chemical reactions are as follows:

${\mathrm{NH}}_4\mathrm{OH}\left(\mathrm{aq}\right)\rightleftharpoons {\mathrm{NH}}_4^{+}\left(\mathrm{aq}\right)+{\mathrm{OH}}^{-}\left(\mathrm{aq}\right)$

$\mathrm{NaOH}\left(\mathrm{aq}\right)\rightleftharpoons {\mathrm{Na}}^{+}\left(\mathrm{aq}\right)+{\mathrm{OH}}^{-}\left(\mathrm{aq}\right)$

Salts:

• When an acid reacts with a base to form salt and water.
• Barium chloride $\mathrm{\left(}{\mathrm{BaCl}}_{\mathrm{2}}\left(s\right)\mathrm{\right)}$ and Sodium chloride $\mathrm{\left(}\mathrm{NaCl}\left(s\right)\mathrm{\right)}$ are salts of acids and bases.
• The chemical reactions are as follows:

$\mathrm{HCl}\left(\mathrm{aq}\right)+\mathrm{NaOH}\left(\mathrm{aq}\right)\to \mathrm{NaCl}\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$

$2\mathrm{HCl}\left(\mathrm{aq}\right)+\mathrm{Ba}{\left(\mathrm{OH}\right)}_2\left(\mathrm{aq}\right)\to {\mathrm{BaCl}}_2\left(\mathrm{s}\right)+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$