Question

Which of the following statements about the steady state approximation is/are correct? The change of intermediate concentration with time is negligible. II. The concentration of the intermediate is assumed zero. III. The rate of intermediate increases initially then reach a plateau. I.

Answer 1

Steady state approximation :

Steady state approximation tells that rate of formation of short lived species like intermediate or transition state is very fast and it is almost equal to rate of its decomposition.

Thus, as these short lived species form, they decompose immediately. So its rate of formation is assumed to be zero.

Example :

A = I₁ = I₂ ​​​​​​........ I_n = B

Here, I₁ , I₂.......I_n are short lived species.

So, according to steady state approximation :

d[I₁]/dt = d[I₂]/dt=.........=d[I_n]/dt = 0

It means the change in concentration of intermediate is zero ,. negligible.

Correct answer : ( 1 )