NEETChemistryChemical Kinetics
A certain reaction A → B follows the given concentration (molarity)-time graph. Which of the following statement is true?
Options
- AThe reaction is of second order with respect to A
- BThe rate for this reaction at 40 second will be approximately 3.5 × 1 0 – 3 M s – 1
- CThe rate for this reaction at 80 second will be 1.75 × 1 0 - 3 M s – 1
- DThe [B] will be 0.25 M at 60 second
Correct answer
B. The rate for this reaction at 40 second will be approximately 3.5 × 1 0 – 3 M s – 1
Step-by-step solution
Time required for concentration to change from 0.4 to 0.2 is same as the time required for the concentration to change from 0.2 to 0.1 , it means t 1/2 is independent of initial concentration, i.e. it is a first order reaction. And from the graph t 1/2 = 20 s ∴ K = 0.693 20 s − 1 ∴ Rate = k[A] At 40 second [A] = 0.1 ∴ rate = 0.693 20 = 3.46 × 10 − 3 Ms − 1 = 3.5 × 10 − 3 s − 1