Solution A Solution B Test Soln Water TO50MI starch Nase 002

Solution A Solution B Test Soln Water TO50MI starch Nase 0.020M 0.10M K2S2O Time 15 15 25 35 69 , 232.5 15 15 M, Vi solution B Calculations 1. Determine the initial concentration, after mixing, of both persulfat e andiodide ions for all trials. 00003 ine the rate for each trial in [iodine) sec. Divide 1.0×10\"MI2by the time in expeu 2. seconds. EXAMPLE: 1.0x10 snexe 3. Using trals 1.2,am3 plot lvg rate vs logelT), Determine q from tisplot ast paae (attach graph) 4. Using trials 3, 4, and 5 plot log rate vs. log([S,Os D. Determine p from this plot. attach graph) 0,9409 uapk. is on the lust page Using the p and q determined in steps 3 and 4 and the measured rate, substitute into the rate equation for each trial and determine k. Calculate the average k 5. Rest calulation in the excel last page

Solution

Quest 1-

a) The oxidation reaction of S₂O₃^2- into S₄O₆^2- favourably requires slightly acidic medium. The equation is given as:

2S₂O₃^2- -----> S₄O₄^2- + 2e^-

hence, on addition of 0.001M acetic acid, the solution becomes weakly acidic and the rate of reaction increases.

b) In the rate law, the exponential of the concentration of persulfate (S₂O₈^2-) is 2 which means the order of the reaction with respect to persulfate concentration is two. therefore on increasing the concentration of persulfate, the rate increases.

c) correctly solved

d) since concentration of S₂O₃^2- is not involved in the rate law, it doesnt affect the rate of reaction. Hence, no change

e) correctly solved

f) correctly solved