Chemical Kinetics Question 343
Question: The hypothetical reaction $ A_2+B_2\xrightarrow{{}}2AB $ ; follows the following mechanism $ A_2\xrightarrow{Fast}A+A, $
$ A+B_2\xrightarrow{slow}AB+B,A+B\xrightarrow{Fast}AB $ The order of the overall reaction is
Options:
A) 0
B) 1
C) 2
D) 3/2
Show Answer
Answer:
Correct Answer: D
Solution:
[d] $ A_2+B_2\xrightarrow{{}}2AB; $
$ A_2\xrightarrow{{}}A+A( Fast ); $
$ A+B_2\xrightarrow{{}}AB+B( Slow ) $ Rate law $ =k[ A ][ B_2 ] $ put value of [A] from 1st reaction since A is intermediate $ \sqrt{k[A_2]}=A $
$ \therefore $ Rate law equation $ =k\sqrt{k[A_2]}[B_2] $
$ \therefore ,Order=\frac{1}{2}+1=\frac{3}{2} $
