Which of the pairs of reactants will NOT result in a displacement reaction?

Question

A. Iodine + sodium chloride

B. Fluorine + sodium chloride

C. Chlorine + sodium iodide

D. Bromine + sodium iodide

Answer 1

The key to this question is the intermolecular forces and properties of the chemicals involved. The sodium in each of these is a spectator ion that stabilizes the anions that may or may not be displaced. All of the anions involve halogens. In general, the reactivity series of halogens gets more reactive to the top of the column.

So F>Cl>Br>I. Iodine has less electronegativity than the other halogens and can be replaced by them, but cannot replace them. Think of it in terms of a tug of war for electrons. FONCl are the four most electronegative elements when neutral, they always win tug of wars against elements with lower electronegativity.