Q10 of 26 Page 1

Show that time required for completion of 3/4th reaction of first order is twice that of half-life of the reaction.

OR


Derive integrated rate equation for rate constant of zero order reaction.


For a first order reaction the integrated rate eqauation are given as:



Where,


t = time required for conc. change of [A]0 to [A]


[A]0 = initial concentration


[A] = final concentration


k = rate constant of reaction


Case I: at t = t1/2, [A] = [A]0/2




Case II: at t = t3/4, [A] = (1-0.75) × [A]0 = 0.25[A]0





Thus from both the cases we can say that



OR


Consider the reaction,



For a zero order reaction we know that the rate of the reaction does not depend on the concentration of the reactant. Thus the rate equation or rate law is given as:



The sign is negative as the concentration of A is decreasing.



Integrating both sides with limits,






Thus the integrated rate equation for zero order is given as,



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