Ans: A. 0.035/min B. 52.5g/h

a Chlorine is an effective disinfectant for swimming pools. However, it loses its efficacy by undergoing photochemical decay under bright sunlight. The following is the data collected from a laboratory study. Time (min) 10 20 30 40 50 60 Concentration of Cl2 (ppm) 2.45 1.74 1.23 0.88 0.62 0.44 (a) Does the reaction satisfy a power law? If so, show how you would apply the method of half-life to measure the order of reaction and the rate constant. (b) Assuming ideal exposure conditions, calculate the hourly injection rate of chlorine to maintain a sterilising Cl2 level of 1 ppm by mass in a pool 25,000 L in volume. (Hint: What type of reactor is the pool? Is there chlorine leaving the pool?) Will the amount be lower if chlorine is delivered hourly on an intermittent basis? a