Chapter 20, Problem 107CP

Lead forms compounds in the +2 and +4 oxidation states. All lead(II) halides are known (and are known to be ionic). Only PbF₄ and PbCl₄ are known among the possible lead(IV) halides. Presumably lead(IV) oxidizes bromide and iodide ions, producing the lead(II) halide and the free halogen:

${\text{PbX}}_4\to {\text{PbX}}_{\text{2}}+{\text{X}}_{\text{2}}$

Suppose 25.00 g of a lead(IV) halide reacts to form 16.12 g of a lead(II) halide and the free halogen. Identify the halogen.