Question

Write balanced equations that describe the following reactions.

a. The dissociation of perchloric acid in water.

b. The dissociation of propanoic acid (CH₃CH₂CO₂H) in water.

c. The dissociation of ammonium ion in water

Short answer

Acids dissociate in water giving hydronium ions.

${\mathrm{HClO}}_4+{\mathrm{H}}_2\mathrm{O}\rightleftharpoons {\mathrm{ClO}}_4^{-}+{\mathrm{H}}_3{\mathrm{O}}^{+}$

${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{COOH}+{\mathrm{H}}_2\mathrm{O}\rightleftharpoons {\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{COO}}^{-}+{\mathrm{H}}_3{\mathrm{O}}^{+}$

${\mathrm{NH}}_4^{+}+{\mathrm{H}}_2\mathrm{O}\rightleftharpoons {\mathrm{NH}}_3+{\mathrm{H}}_3{\mathrm{O}}^{+}$

Step-by-step solution

The dissociation of perchloric acid in water

Perchloric acid gives ${\mathrm{H}}_3{\mathrm{O}}^{+}$and ${{\mathrm{ClO}}_4}^{-}$ions in solution.

${\mathrm{HClO}}_4+{\mathrm{H}}_2\mathrm{O}\rightleftharpoons {\mathrm{ClO}}_4^{-}+{\mathrm{H}}_3{\mathrm{O}}^{+}$

The dissociation of propanoic acid (CH3CH2CO2H) in water

Propanoic acid gives ${\mathrm{H}}_3{\mathrm{O}}^{+}$and ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{COO}}^{-}$ions in solution.

${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{COOH}+{\mathrm{H}}_2\mathrm{O}\rightleftharpoons {\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{COO}}^{-}+{\mathrm{H}}_3{\mathrm{O}}^{+}$

The dissociation of ammonium ions in water

The ammonium ion gives ${\mathrm{NH}}_3$and ${\mathrm{H}}_3{\mathrm{O}}^{+}$ions in solution.

${\mathrm{NH}}_4^{+}+{\mathrm{H}}_2\mathrm{O}\rightleftharpoons {\mathrm{NH}}_3+{\mathrm{H}}_3{\mathrm{O}}^{+}$