When toluene reacts with chlorine gas in the presence of an iron(III) catalyst, the product is a

Question:

When toluene reacts with chlorine gas in the presence of an iron(III) catalyst, the product is a mixture of the ortho and para isomers of C6H4ICH3. However, when the reaction is light-catalyzed with no Fe3+ catalyst present, the product is C6H5CH2CI. Explain.