Derive an expression to calculate


Derive an expression to calculate the time required for completion of the zero-order reaction.


Consider a reaction,

R → P t=0

Here R is the reactant and P is the product.

Rate = k[R]0 t=t

(Instantaneous rate) –dR/dt = k , dR =-kdt

On integrating both sides,

ʃDr = -k ʃdt

[R] = -kt + I


At t = 0,

[R]= [R0] which makes I= R0


[R] = [R0]– kt. ……………(i)


Here [R] = concentration of reactant at time ‘t’.

[R0] = initial concentration of the reactant.


This reaction is known as the integrated rate equation of zero order.

After completion of zero order reaction [R]= 0

Using [R]= 0 in (i)




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