In a pseudo first order hydrolysis of ester in water, the following results were obtained
t/s | 0 | 30 | 60 | 90 |
[Ester]/mol L-1 | 0.55 | 0.31 | 0.17 | 0.085 |
(i) Calculate the average rate of reaction between the time interval 30 to 60 seconds
(ii) Calculate the pseudo first-order rate constant for the hydrolysis of the ester.
(i) Average rate of reaction over interval is [change in concentration]/[time taken] i.e.
(ii) the pseudo first-order rate constant can be calculated by
K = (2.303/t) log(Ci/Ct) where K is Rate constant,
t is time taken,
Ci is initial concentration
Ct is Concentration at time t.
K = (2.303/30) log (0.55/0.31)
⇒ K = 1.9 × 10-2 sec-1
(i) Average rate between 30 to 60 sec is 0.00467 mol L-1sec-1
(ii) Pseudo first order rate constant is 1. × 10-2sec-1
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