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From the following data, show that the decomposition of hydrogen peroxide is a reaction of the first order : {:(t,,,0,,,10,,,20),(x,,,46.1,,,29.8,,,19.3):} where t is the time in minutes and x is the volume of standard KMnO_(4) solution in "cm"^(3) required for titrating the same volume of the reaction mixture. |
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Answer» Solution :Volume of `"KMnO"_(4)` solution used `prop`amount of `H_(2)O_(2)` present. Hence, ifthe given reaction is of the first order, it must obey the equation : `k=(2.303)/(t)log""(a)/(a-x)=(2.303)/(t)log""(V_(0))/(V_(t))` (Note that the SYMBOL x in the numerical PROBLEM isin FACT `a-x, i.e., V_(t)`) In the present CASE, `V_(0)=46.1" cm"^(3)` The value of k at each instant can be calculated as follows: `{:("t (min)",,,V_(t),,,""k=(2.303)/(t)log""(V_(0))/(V_(t))),(10,,,29.8,,,k=(2.303)/(10min)log""(46.1)/(29.8)=0.0436min^(-1)),(20,,,19.3,,,k=(2.303)/(20min)log""(46.1)/(19.3)=0.0435min^(-1)):}` Thus, the value of k comesout to be nearly constant. Hence, it is a reaction of the first order. |
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