Heavier halide is oxidised by lighter halogen. Justify. 

Explanation

The oxidation ability of halogens is in the order : `F_(2) gt Cl_(2) gt Br_(2) gt I_(2)`.
Lighter halogen is a stronger oxidant. Heavier halide is less stable, acts as a reducing agent and is easily oxidised.
The reaction that is easily possible among halides and halogens is, `2I^(-)+F_(2)rarr 2F^(-)+I_(2)`