Chemistry Individual Investigation (F336) - Starter Page 4The kinetics of the reaction between propanone and iodine

Propanone reacts with iodine according to the following equation:CH3COCH3 + I2 CH3COCH2I + H+ + IThe reaction is catalysed by hydrogen ions.You can measure the rate of reaction by using a colorimeter to monitor the production of iodine over time.Your first task is to carry out some preliminary experiments to work out what are suitable amounts of solutions to mix together

Requirementsiodine solution 0.020 mol dm3propanone solution, 2.0 mol dm3hydrochloric acid, 2.0 mol dm3

Getting started Choose an appropriate filter for your colorimeter to measure the concentration of iodine. Zero the colorimeter using water. Use a burette to measure 2.0 cm3 of propanone solution into a boiling tube. Mix 1.0 cm3 iodine solution, 2.0 cm3 hydrochloric acid and 5.0 cm3 water in a second boiling tube. Add the two solutions together and start a stop watch. Use a dropping pipette to add some of the reaction mixture to a cuvette and place in the colorimeter. Take the absorbance reading every 30 seconds for six minutes.Are the volumes and concentrations of solutions suitable or do you need to modify them?When you are satisfied that you have appropriate solutions you can change the concentration of the solutions carefully and accurately to achieve a sufficient number of results that will allow you to draw a graphs that will let determine the order of reaction for one of the reactants.