Question

Difference between Common Ion Effect and Odd Ion Effect.

Answer 1

Common Ion Effect	Odd Ion Effect
NH4OH ⇌ NH4+ + OH–  On mixing NH4Cl NH4Cl →NH4+ + Cl–	NH4OH ⇌ NH4+ + OH–  On mixing HCl HCl → H+ + Cl–
Due to mixing of common ion concentration of ammonium ion will increase therefore equilibrium will shift in backward direction i.e. rate of backward reaction increases means α decreases.	Due to mixing of odd ions concentration of OH– will decrease  ∴ Equilibrium will shift in forward direction i.e. rate of forward reaction increases, means α increases