viii. Solubility of a sparingly soluble salt get affected in presence of a soluble salt having one common ion. Explain.
4. Answer the following :
viii. Solubility of a sparingly soluble salt get affected in presence of a soluble salt having one common ion. Explain.
i. The presence of a common ion has an impact on the solubility of sparingly soluble salts.
ii. Consider the solubility equilibrium of AgCl,
\[\ce{AgCl_{(s)} ⇌ Ag^+_{(aq)} + Cl^-_{(aq)}}\]
The solubility product of AgCl is given by
Ksp = [Ag+][Cl-]
iii. Let's introduce AgNO3 into the saturated solution of AgCl. AgNO3, being a strong electrolyte, completely dissociates in the solution:
\[\ce{AgNO_{3(aq)} ⇌ Ag^+_{(aq)} + NO_3^-_{(aq)}}\]
iv. The dissociation of both AgCl and AgNO3 leads to the presence of a common Ag+ ion. The concentration of Ag+ ions in the solution increases due to the complete dissociation of AgNO3.
v. Following Le-Chatelier's principle, the addition of Ag+ ions from AgNO3 to the AgCl solution shifts the solubility equilibrium of AgCl to the left. The reverse reaction, where AgCl precipitates, becomes favored until the solubility equilibrium is re-established.
vi. However, the value of Ksp remains constant since it represents an equilibrium constant. Consequently, the solubility of sparingly soluble compounds decreases in the presence of a common ion in the solution.