Question

The reaction of ozone with oxygen atoms in the presence of chlorine atoms can occur by a two step process shown below :
$O_3(g)+C{l}^{\ast }(g)\to O_2(g)+Cl{O}^{\ast }(g)\dots (i)$
$[k_i=5.2\times 10^{9}Lmo{l}^{-1}{s}^{-1}]$
$Cl{O}^{\ast }(g)+O^{\ast }(g)\to +C{l}^{\ast }(g)\dots (ii)$
$[k_{ii}=2.6\times 10^{10}Lmo{l}^{-1}{s}^{-1}]$
The closest rate constant for the overall reaction
$O_3(g)+O^{\ast }(g)\to 2O_2(g)$ is :

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

Answer 1

Answer: (D)

$O_3(g)+C{l}^{\prime }(g)\to O_2(g)+ClO(g)\dots .$ (i) $k_i=5.2\times 10^{9}Lmo{l}^{-1}{s}^{-1}$
$Cl{O}^{\prime }(g)+O^{\prime }(g)\to O_2(g)+C{l}^{\prime }(g)\dots$ (ii) $k_{ii}=2.6\times 10^{10}Lmo{l}^{-1}{s}^{-1}$
For overall reaction, equation (i)+(ii)
$O_3(g)+O(g)\to 2O_2(g)<br/>Thenoverallreactionconstantwillbe$k _{ i } \times k _{ ii }$.<br/>So,overallreactionconstantis$1.4 \times 10^{20} Lmol ^{-1} s ^{-1}$.