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In a first order reaction, 75% of the re...

In a first order reaction, `75%` of the reactants disappeared in `1.386 hr`. What is the rate constant ?

A

`3.6xx10^(-3) s^(-1)`

B

`2.8xx10^(-4) s^(-1)`

C

`17.2xx10^(-3) s^(-1)`

D

`1.8xx10^(-3) s^(-1)`

Text Solution

Verified by Experts

The correct Answer is:
B
75% disappears in 1.388 hr. so 50% disappears in `(1.388)/(2) hr`
or `0.694" hr. k"=(0.693)/(t_(1//2))=(0.693)/(0.694xx60xx60)"sec"^(-1)~~(100)/(36)xx10^(-4)s^(-1)=2.8xx10^(-4) s^(-1)`
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