Question

For the reaction, $2NO+{Cl}_2⟶2NOCl$, the following mechanism has been proposed:
$NO+{Cl}_2\rightleftharpoons NO{Cl}_2$ (fast)
$NO{Cl}_2+NO⟶2NOCl$ (slow)
The rate law for the reaction is:

• A. Rate $=k{\left[NO\right]}^2\left[{Cl}_2\right]$
• B. Rate $=k\left[NO\right]{\left[{Cl}_2\right]}^2$
• C. Rate $=k\left[NO{Cl}_2\right]$
• D. Rate $=k{\left[NOCl\right]}^2$

Answer 1

The correct option is A Rate $=k{\left[NO\right]}^2\left[{Cl}_2\right]$

Rate $=k^{{}^{\prime }}\left[NO\right]\left[NO{Cl}_2\right]=k^{{}^{\prime }}K\left[NO\right]\left[NO\right]\left[{Cl}_2\right]=k{\left[NO\right]}^2\left[{Cl}_2\right]$