AQA Jan 2010 Paper 4 Q3

Answers available below

areas outside the box will not be scanned for marking propanone and iodine react in acidic conditions according to the following equation ch coch i ich coch hi a student studied the kinetics of this reaction using hydrochloric acid and a solution containing propanone and iodine from the results the following rate equation was deduced rate k ch coch h a give the overall order for this reaction mark b when the initial concentrations of the reactants were as shown in the table below the initial rate of reaction was found to be mol dm s ch coch i h initial concentration mol dm use these data to calculate a value for the rate constant k for the reaction and give its units calculation units marks c deduce how the initial rate of reaction changes when the concentration of iodine is doubled but the concentrations of propanone and of hydrochloric acid are unchanged mark wmp jan chem areas outside the box will not be scanned for marking d the following mechanism for the overall reaction has been proposed step ch coch h h c c ch oh step h c c ch oh ch h oh step step ch i oh ch i ich c o ch ich c o ich c ch h use the rate equation to suggest which of the four steps could be the rate determining step explain your answer rate determining step explanation marks e use your understanding of reaction mechanisms to predict a mechanism for step by adding one or more curly arrows as necessary to the structure of the carbocation below step h c c ch oh ch h oh mark turn over wmp jan chem

Show answer