Explain the catalytic action of Iron(III) in the reaction between `I and S_(2)O_(8)^(2-)` ions.

Explanation

Transition metal ions can change their oxidation states and become more effective catalysts. Iron (III) Catalyses the reaction between iodide and per sulphate ions
`2I^(-)+S_(2)O_(8)^(-2)overset(Fe^(+3))rarrI_(2)+2SO_(4)^(-2)`
Catalytic action explained as follows
`2Fe^(+3)+2I^(-)rarr2Fe^(+2)+I_(2)`
`2Fe^(+2)+S_(2)O_(8)^(-2)rarr2Fe^(+3)+2SO_(4)^(-2)`