The acid ionization constant of Zn^2+ is 2.0 × 10^-10. What is the basic dissociation constant of Zn — Ionic Equilibrium Chemistry Question

💡 Solution & Explanation

The acid ionization constant of Zn^2+ corresponds to: Zn^2+(aq) + $H_2O$ ⇌ Zn(OH)+(aq) + H+(aq) (Ka = 2.0 × 10^-10).<br>The basic dissociation of Zn(OH)+ corresponds to: Zn(OH)+(aq) ⇌ Zn^2+(aq) + OH-(aq) (Kb).<br>Since the sum of these reactions is the auto-ionization of water ($H_2O$ ⇌ H+ + OH-), we have Ka × Kb = Kw = 10^-14.<br>Kb = Kw / Ka = 10^-14 / (2.0 × 10^-10) = 5.0 × 10^-5.