Question

A first order reaction is half completed in 45mins .the time required for the completion of99.9% of the reaction is?

Answer 1

Answer:

Explanation:

The equation of the First order reaction is

t=1kln(A0A)

Now After 20% completion, 0.8A0 will be left.

So

k=120ln(108)

Now you got k.

So Now put A=A0/4in the equation and Put value of K to get your answer of t. :D