Chemical Kinetics Question 158
Question: The order of the reaction occurring by following mechanism should be [JIPMER 1997] (i) $ A_2\to A+A $ (fast) (ii) $ A+B_2\to AB+B $ (slow) (iii) $ A+B\to $ (fast)
Options:
A) $ 1,\frac{1}{2} $
B) $ 3\frac{1}{2} $
C) 2
D) None of these
Show Answer
Answer:
Correct Answer: A
Solution:
The rate will be given by slowest step. Thus $ r=K[A][B_2] $ . $ K_{c}=\frac{[A][A]}{[A_2]} $ or $ [A]={{[K_{c}]}^{1/2}}{{[A_2]}^{1/2}} $
$ r=K\times {{[K_{c}]}^{1/2}}{{[A_2]}^{1/2}}[B_2]=K{{[A_2]}^{1/2}}[B] $ . Thus order is $ 0.5+1=1.5 $
