Derive an expression to calculate

Solution:

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)

[R0]=kt

 

t=[R0]/k