Exhibit 18-3 The following question(s) pertain to the reaction of propene (C3CHCH2) with hydrochloric acid. $\mathrm{HCl}+\mathrm{C}_{3} \mathrm{CHCH}_{2} \leftrightarrows \mathrm{CH}_{3} \mathrm{CHClCH}_{3}$ A proposed mechanism for this chemical reaction is $\begin{array}{ll}
\mathrm{HCl}+\mathrm{HCl} \leftrightarrows \mathrm{H}_{2} \mathrm{Cl}_{2}& \text { (fast, equilibrium) } \
\mathrm{HCl}+\mathrm{C}_{3} \mathrm{CHCH}_{2} \leftrightarrows \mathrm{CH}_{3} \mathrm{CHClCH}_{3}{ }^{*} & \text { (fast, equilibrium) } \
\mathrm{CH}_{3} \mathrm{CHClCH}_{3}{ }^{*}+\mathrm{H}_{2} \mathrm{Cl}_{2} \rightarrow \mathrm{CH}_{3} \mathrm{CHClCH}_{3} \rightarrow 2 \mathrm{HCl} & \text { (slow) }
\end{array}$

Refer to Exhibit 18-3. If the first step were the slow step, what would be the predicted order of the reaction with respect to propene?

Question

Exhibit 18-3 The following question(s) pertain to the reaction of propene (C3CHCH2) with hydrochloric acid. $\mathrm{HCl}+\mathrm{C}_{3} \mathrm{CHCH}_{2} \leftrightarrows \mathrm{CH}_{3} \mathrm{CHClCH}_{3}$ A proposed mechanism for this chemical reaction is $\begin{array}{ll}
\mathrm{HCl}+\mathrm{HCl} \leftrightarrows  \mathrm{H}_{2} \mathrm{Cl}_{2}& \text { (fast, equilibrium) } \
\mathrm{HCl}+\mathrm{C}_{3} \mathrm{CHCH}_{2} \leftrightarrows \mathrm{CH}_{3} \mathrm{CHClCH}_{3}{ }^{*} & \text { (fast, equilibrium) } \
\mathrm{CH}_{3} \mathrm{CHClCH}_{3}{ }^{*}+\mathrm{H}_{2} \mathrm{Cl}_{2} \rightarrow \mathrm{CH}_{3} \mathrm{CHClCH}_{3} \rightarrow 2 \mathrm{HCl} & \text { (slow) }
\end{array}$

Refer to Exhibit 18-3. If the first step were the slow step, what would be the predicted order of the reaction with respect to propene?

Quizplus · Accepted Answer

The first step is the formation of HCl2-, which is a fast equilibrium step. The second step is the reaction of HCl2- with propene, which is also a fast equilibrium step. The third step is the slow step, which is the reaction of the intermediate with HCl2- to form the product. The order of the reaction with respect to propene is therefore 0.

Exhibit 18-3 the Following Question(s) Pertain to the Reaction of Propene