Chlorate (clo3 − ) is a toxic anion in polluted water from the use of high energy materials, herbicide, and drinking water disinfection with chlorine chemicals. in a reaction for the catalytic reduction of clo3 − into the non-toxic chloride (cl− ), the reaction rate constant was measured as 9.98 hr−1 , then how many minutes does the reaction take to reduce 90% of the chlorate in the water?

Along steel shaft of 10 cm diameter is austenised at 870°c and then quenched in a liquid at 30oc. the average surface heat transfer coefficient is 2000 w/m2. °c. the relevant thermophysical properties of the shaft are: p=7800 kg/m", k=20 w/mk, cp=0.46 kj/kg. k calculate: a)-the time required for the center temperature to drop to 200°c. b)-the temperature at half-radius at that moment. c)-the amount of heat that had been transferred to the liquid by that time per meter length of the shaft