Nature of the Reactants Simple reactants will react at a faster rate than more complex reactants

Nature of the Reactants
Simple reactants will react at a faster rate than more complex reactants.
Consider the following two reactions;
4 (aq) (aq)a) MnO + Fe ——-> products (fast) -2+ 4 (aq) 2 4 (aq)b) MnO + C O —–>products (slow) -2
4Permanganate (MnO ) ions in solutions produce a deep purple colour. In the first example, the relatively simple iron ions cause the decolourization of permanganate to occur instantaneously. In the second case, the decolourization occurs very slowly. The oxalate ions involve bonds between carbon atoms as well as bonds between carbon & oxygen atoms. Since energy will be required to break these bonds first, the formation of products must occur at a slower rate. Similarly, a reaction where the products are in a 1:1 mol ratio should also occur at a faster rate.
(aq) (aq)Eg. Ag + Cl ——-> AgCl(s) (fast)