Question

The reaction $A_2+B_2\to 2AB$ occurs in the following steps
$A_2\to A+A$ (slow)
$A+B_2\to AB+B$ (fast)
$A+B\to AB$ (fast)
The order of reaction is:

• A. $\frac{3}{2}$
• B. $2$
• C. zero
• D. $1$

Answer 1

The correct option is D $1$

Rate Determining step is always the slow initial step but not the fast one.

So, the Rate is

$rate=k\left[A_2{]}^1\right[B_2{]}^0$

So the Order of the reaction is 1