The pH of acidic buffer increases by adding more salt in it because:
Correct answer: B. Dissociation of acid is decreased.
- A. Dissociation of acid is increased.
- B. Dissociation of acid is decreased.
- C. Added salt produces more OH- ions.
- D. Added salt increases pKa of acid.
Explanation
This is the correct explanation. When more salt (containing the conjugate base) is added to an acidic buffer, the common ion effect reduces the dissociation of the weak acid. This helps maintain the pH of the solution within a specific range. The equilibrium shifts towards the non-dissociated form of the weak acid, which leads to a decrease in the dissociation of the acid.
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About Chemical Equilibrium
Reversible reactions reach dynamic equilibrium when forward and reverse rates become equal, and Le Chatelier's principle predicts the effect of changing concentration, pressure or temperature. The chapter also covers solubility product, the common ion effect, buffer action and the conditions used in Haber's process, with equilibrium shifts distinguished from changes in the equilibrium constant.
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