For a first order reaction (A) -----> Products the concentration of A changes from 0.1M to 0.025M in 40minutes. The rate of reaction when the concentration of A is 0.01A is :
(A) 1.73 x 10-5M/min
(B) 3.47 x 10-4M/min
(C) 3.47 x 10-5M/min
(D) 1.73 x 10-4M/min
To find rate of the reaction we first need to find the rate constant, which can be done as follows:
where, t = 40min
[A]1 = 0.1 M
[A]2 = 0.025 M
For a first order reaction Rate law can be written as:
Rate = k [A]
When [A] = 0.01 M
Rate = 3.4 x 10-2 x 0.01
Rate = 3.4 x 10-4 M/min