(N/A) Ionic equilibrium is the state of dynamic equilibrium established between the unionized molecules and the ions in an aqueous solution of an electrolyte.
Example: $Fe_{(aq)}^{3+} + SCN_{(aq)}^{-} \rightleftharpoons [Fe(SCN)]_{(aq)}^{2+}$
Substances can be classified based on their behavior in solution:
$1$. Non-electrolytes: Substances like sugar do not conduct electricity in aqueous solution because they do not produce ions. Thus,ionic equilibrium does not occur in non-electrolytic substances.
$2$. Strong Electrolytes: These substances are almost $100 \%$ ionized in water. For example,$NaCl$ is a strong electrolyte. In these solutions,ionic concentration and conductivity are high,and the reaction proceeds almost to completion.
$3$. Weak Electrolytes: These substances are ionized to a small extent (usually less than $5 \%$) in solution. In weak electrolytes,a dynamic equilibrium is established between the ions and the unionized molecules.
Example: $CH_{3}COOH_{(aq)} \rightleftharpoons CH_{3}COO_{(aq)}^{-} + H_{(aq)}^{+}$
Ionic equilibrium is typically established in solutions of weak acids,weak bases,and their salts.