Question

The reaction of ozone with oxygen atoms in the presence of chlorine atoms can occur by a two step process shown below:



The closest rate constant for the overall reaction

$O_3\left(g\right)+O^{\cdot }\left(g\right)\to 2O_2\left(g\right)$ is:

• A. $1.4\times 10^{20}Lmo{l}^{-1}{s}^{-1}$
• B. $3.1\times 10^{10}Lmo{l}^{-1}{s}^{-1}$
• C. $5.2\times 10^{9}Lmo{l}^{-1}{s}^{-1}$
• D. $2.6\times 10^{10}Lmo{l}^{-1}{s}^{-1}$

Answer 1

Answer: (A)

$$\begin{gathered} O_{3\left(g\right)}+C{l}_{\left(g\right)}^{\cdot }{\to }_{}^{}{O}_{2\left(g\right)}+Cl{O}_{\left(s\right)}^{\cdot }{K}_i \\ Cl{O}_{\left(g\right)}^{\cdot }+O_{\left(g\right)}^{\cdot }{\to }_{}^{}{O}_{2\left(g\right)}+C{l}_{\left(g\right)}^{\cdot }{K}_{ii} \end{gathered}$$

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$O_{3\left(g\right)}+O_{\left(g\right)}^{\cdot }{\to }_{}^{}{\left(20\right)}_{2\left(g\right)}{K}_{Rate}=K_i\times K_{ii}$

Overall Rate constant = K_i × K_ii

= 5.2 × 10⁹ × 2.6 × 10¹⁰

≈ 1.4 × 10²⁰ mol^-1 L s^-1