Full Question : Qn8http://www.rsc.org/images/2000_Rd%20_1_Questions_tcm18-190754.pdf
Answers (not full working though)http://www.rsc.org/images/2000_Rd_1_Answers_tcm18-190755.pdf
Thing is, I'm unable to obtain the value of k as 0.112 (the given answer).
My method :
Since order of reaction wrt to I3- is 1, and since
rate = c [I3–]^1 where c = k [H3AsO3]^1 [H+]^-1 [I–]^-2,
accordingly using c = ln2/t(1/2) (for any one of the 4 Runs) and substituting both the value of c, as well as the molarities of the other species (for that particular Run) into the equation
c = k [H3AsO3]^1 [H+]^-1 [I–]^-2
we should be able to obtain the value of k, which based on the 4 Runs, are approximately 0.12 to 0.13 (to 2 sf), but the given answer is 0.11 (to 2 sf).
Any assistance would be much appreciated.