What Is a Halogen Displacement Reaction?

A halogen displacement reaction occurs when a more reactive halogen displaces a less reactive halogen resulting in a new compound. The generic formula is X+AY --> Y+ AX, where X and Y are different halogens.

Halogens

Halogens comprise a group of nonmetal elements having seven valence electrons. They are fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), and Astatine (At). All are located in Group VII of the periodic table.

Displacement Reactions

Displacement reactions occur when an element displaces another element in a compound and are not confined to halogens.

Reactivity of Halogens

Halogens are extremely reactive with many substances, even some that are otherwise inert. In nature, halogens exist in compounds or as ions.

Order of Reactivity

In halogens, the order of reactivity decreases going down the column on the periodic table with fluorine the most reactive and astatine the least reactive.

Example of a Halogen Displacement Reaction

Fluorine reacts with potassium iodide to displace the iodine and produce iodine and potassium chloride. Equation: Fl2 + 2 KI --> I2 + 2 KFl.

References

• Single Displacement Reactions
• Halogens
• The Chemistry of the Halogens

Resources

• Periodic Table of the Elements