Question

Which of the following pairs will show common ion effect ?

• A. barium chloride + barium sulphate
• B. silver cyanide + potassium nitrite
• C. ammonium hydroxide + ammonium chloride
• D. sodium chloride +hydrogen chloride

Answer 1

Answer: (C)

Common ion effect is the suppression of degree of dissociation of weak electrolyte on adding a strong electrolyte having an ion common. Since, ammonium hydroxide is a weak electrolyte and ammonium chloride is a strong electrolyte having common ammonium ion, thus $N{H}_{4}Cl$ decreases the degree of dissociation of $N{H}_{4}OH$.

Hence, $N{H}_{4}Cl+N{H}_{4}OH$ exhibits common ion effect.