The reaction of CO with Cl gives phosgene (COCl), a nerve...

The reaction of CO with Cl_ gives phosgene (COCl_), a nerve gas that was used in World War I. Use the mechanism shown here to complete the following exercises: $\mathrm{Cl}_{2}(g) \rightleftharpoons 2 \mathrm{Cl}(g)$ (fast, $\mathrm{k}_{1}$ represents the forward rate constant, $k_{-1}$ the reverse rate constant) $\mathrm{CO}(g)+\mathrm{Cl}(g) \longrightarrow \operatorname{COCl}(g)$ (slow, $k_{2}$ the rate constant) $\operatorname{COCl}(g)+\operatorname{Cl}(g) \longrightarrow \operatorname{COCl}_{2}(g)$ (fast, $k_{3}$ the rate constant) (a) Write the overall reaction. (b) Identify all intermediates. (c) Write the rate law for each elementary reaction. (d) Write the overall rate law expression.

The reaction of CO with Cl_ gives phosgene (COCl_), a nerve gas that was used in World War I. Use the mechanism shown here to complete the following exercises:
$\mathrm{Cl}_{2}(g) \rightleftharpoons 2 \mathrm{Cl}(g)$ (fast, $\mathrm{k}_{1}$ represents the forward rate constant, $k_{-1}$ the reverse rate constant) $\mathrm{CO}(g)+\mathrm{Cl}(g) \longrightarrow \operatorname{COCl}(g)$ (slow, $k_{2}$ the rate constant)
$\operatorname{COCl}(g)+\operatorname{Cl}(g) \longrightarrow \operatorname{COCl}_{2}(g)$ (fast, $k_{3}$ the rate constant)
(a) Write the overall reaction.
(b) Identify all intermediates.
(c) Write the rate law for each elementary reaction.
(d) Write the overall rate law expression.

Key Concepts

Pre-Equilibrium Approximation

The pre-equilibrium approximation applies when an early step in the mechanism is fast and reversible, reaching equilibrium well before the slower, subsequent step occurs. This allows the concentration of an intermediate to be expressed in terms of the concentrations of the reactants, simplifying the derivation of the overall rate law.

Reaction Mechanism

A reaction mechanism is a detailed description of the step?by?step sequence by which reactants transform into products. It breaks down the overall process into elementary reactions, each with its own rate law that contributes to understanding the kinetics and dynamics of the overall chemical transformation.

Elementary Reactions

Elementary reactions are single, indivisible steps in a reaction mechanism where the molecularity directly dictates the rate law. Their rate expressions can be written using the stoichiometric coefficients as exponents of the concentrations of the reactants involved in that step.

Rate-Determining Step

The rate-determining step is the slowest elementary reaction in the mechanism, and it controls the overall reaction rate. Because its rate is much slower than the other steps, the kinetics of the entire process can usually be approximated by the kinetics of this step.

Reaction Intermediates

Reaction intermediates are transient species that are produced in one step of a mechanism and consumed in a subsequent step. They do not appear in the overall balanced chemical equation but are crucial for understanding the pathway and rate of the reaction.

Transcript

Please give Ace some feedback