Lead forms compounds in the 12 and 14 oxidation states. All lead(II) halides are known (and are

Question:

Lead forms compounds in the 12 and 14 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:
PbX4 → PbX2 + X2
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.