4. (20 points) A water supply with a pH of 7.5 contains 100 ug/L of Br (MWBr = 79.9 g/mol). You would like to evaluate the risks of forming the probable human carcinogen bromate (BrO3 ) during treatment of this water with 25 uM of ozone (O3), on the basis of the unbalanced redox half-reactions shown below: aO3(aq) + bH* + ce dO2(aq) + H2O E = 2.050 V Br fBrO3 + 3H+ + he iBr + jH20 E = 1.423 V Bromate (Br03) (a) (10/20 points) Balance each of the above half-reactions. Clearly show the oxidation states of all reactants and products. (Note: You can assume an average oxidation state of 0 for the oxygen atoms in ozone.) (b) (5/20 points) Derive the overall balanced expression for the reaction of Oz with Br to yield BrO; (c) (5/20 points) Do you expect this reaction to be thermodynamically favorable under the conditions of this system? Remember that AE = AE - (0.059)*logQ. Please explain your answers. (Note: You can assume that [O2(aq)] = 1.25 mM, and that [BrO3 ] cannot exceed (Br Jo on a molar basis.)