This could be a double replacement reaction (specifically, precipitation) if an insoluble product is formed. So swap the partners to potassium chloride and iron sulfate and determine if a precipitate will form (this will drive the reaction). All potassium compounds are soluble and chlorides are mostly soluble with 3 exceptions - soluble. The rule usually given for sulfates is "sulfates are soluble, except for silver, lead, mercury(I) and the heavy IIAs (Group 2: Ba and Sr with Ca marginal). Your answer is that the ions are all floating around in the solution and nothing happens.
