Chapter 18, Problem 18.102QE

At 298 K, the solubility product constant for Pb(IO₃)₂ is 2.6 × 10⁻¹³, and the standard reduction potential of the Pb²⁺(aq) to Pb(s) is −0.126 V.

1. (a) Find the standard potential of the half-reaction

$\text{Pb}{({\text{IO}}_3)}_2(\text{s})+2{\text{e}}^{-}\to \text{Pb}(\text{s})+2{\text{IO}}_3^{-}(\text{aq})$

(Hint: The desired half-reaction is the sum of the equations for the solubility product and the reduction of Pb²⁺. Find ΔG° for these two reactions, and add them to find ΔG° for their sum. Convert the ΔG° to the potential of the desired half-reaction.)

1. (b) Calculate the potential of the Pb/Pb(IO₃)₂ electrode in a 3.5 × 10⁻³ M solution of NaIO₃.