Question

What is common Ion effect explain with suitable example

Answer 1

Some of the salt will be precipitated until the ionproduct is equal to the solubility product. In short, the common ion effect is the suppression of the degree of dissociation of a weak electrolyte containing a common ion.

Answer 2

$\textbf{\large{Answer -}}$

To the solution of weak electrolyte a salt solution having common ion is added then the dissociation of weak electrolyte is suppressed. This effect is known as $\textbf{commom ion effect.}$

For Example :

In presence of $CH_{3}COONa$ , dissociation of $CH_{3}COOH$ is suppressed.

Explanation :

$CH_{3}COOH$ is weak electrolyte and are dissociated as follow -

$CH_{3}COOH (aq) ==> CH_{3}{COO}^{-} + {H}^{+}$

$CH_{3}COONa$ is a strong electrolyte and are dissociated as follow -

$CH_{3}COONa ==> CH_{3}{COO}^{-}+ {Na}^{+}$

Due to presence of common ion i.e., $CH_{3}{COO}^{-}$ ion, the concentration of $CH_{3}{COO}^{-}$in solution is increased and according to Le-Chatelier Principle, the equilibrium will shift in backward direction i.e., dissociation of acetic acid is suppressed.