12.7 Catalysis

Account for the increase in reaction rate brought about by a catalyst.

Consider this scenario and answer the following questions: Chlorine atoms resulting from decomposition of chlorofluoromethanes, such as CCl₂F₂, catalyze the decomposition of ozone in the atmosphere. One simplified mechanism for the decomposition is:
$\begin{matrix} \\ \\ \text{O}_{3} \overset{ \text{sunlight} }{\rightarrow} \text{O}_{2} + \text{O} \\ \text{O}_{3} + \text{Cl} \rightarrow \text{O}_{2} + \text{ClO} \\ \text{ClO} + \text{O} \rightarrow \text{Cl} + \text{O}_{2}\end{matrix}$

(a) Explain why chlorine atoms are catalysts in the gas-phase transformation:
$2 \text{O}_{3} \rightarrow 3 \text{O}_{2}$

(b) Nitric oxide is also involved in the decomposition of ozone by t…

Consider the similarities and differences in the two reaction diagrams shown in the exercise. Do these diagrams represent two different overall reactions, or do they represent the same overall reaction taking place by two different mechanisms? Explain your answer.

Water gas is a 1:1 mixture of carbon monoxide and hydrogen gas and is called water gas because it is formed from steam and hot carbon in the following reaction: $\text{H}_{2} \text{O} \left(g\right) + \text{C} \left(s\right) \rightleftharpoons \text{H}_{2} \left(g\right) + \text{CO} \left(g\right) .$ Methanol, a liquid fuel that could possibly replace gasoline, can be prepared from water gas and hydrogen at high temperature and pressure in the presence of a suitable catalyst. What will happen to the concentrations of H₂, CO, and CH₃O…