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Question
The rate constant for the first-order decomposition of H2O2 is given by the following equation:
`logk=14.2-(1.0xx10^4)/TK`
Calculate Ea for this reaction and rate constant k if its half-life period be 200 minutes.
(Given: R = 8.314 JK–1 mol–1)
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Solution
Given:
Order of the reaction = First order
t1/2 = 200 minutes = 200 × 60 = 12,000 seconds
The relation between t1/2 and k is given by
t1/2 = 0.693/k
k = 0.693/12000 = 5.7 × 10−5
The rate constant for the first-order decomposition of H2O2 is given by
`logk=14.2-(1.0xx10^4)/TK...................(i)`
By Arrhenius equation
`log k=logA-E_a/(2.303RT)...............(ii)`
Comparing (i) and (ii), we get
Ea = 1.91 × 105
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