Question

Assertion :For the reaction given below, the molecularity of first step is 1 and of second step is 2.
$2O_3\left(g\right)\to 3O_2\left(g\right)$
Step 1 $O_3\left(g\right)\rightleftharpoons O_2\left(g\right)+O\left(g\right)$
Step 2 $O_3\left(g\right)+O\stackrel{slow}{\to }2O_2\left(g\right)$ Reason: O(g) is an intermediate and rate of reaction is $K\left[O_3{]}^2\right[O_2{]}^{-1}$ and order of reaction is 1.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Assertion is incorrect but Reason is correct

Answer 1

The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

Option (A) is correct.
Rate constant of the reaction is given by :
$K_c=\frac{\left[O_2\right]\left[O\right]}{\left[O_3\right]}$
$rate=K\left[O_3\right]\left[O\right]=\frac{K_c\left[O_3\right]\times \left[O_3\right]}{\left[O_2\right]}$
$=\frac{K^1[O_3{]}^2}{\left[O_2\right]}$