Chemistry Practice Problems Nuclear Transmutation Practice Problems Solution: The steady-state stratospheric ozone concentration...

Solution: The steady-state stratospheric ozone concentration, which is determined by a balance between photochemical production and dissociation, has been offset by the presence of long-lived chlorofluorocarbons (CFCs) released in the troposphere through anthropogenic activity. According to the following mechanism, ozone depletion requires ________ radiation to initiate a chain reaction in which ________ serves as the catalyst.CFCl3 + hν → CFCl2• + Cl•Cl• + O3 → ClO• + O2ClO•+ O3 → Cl• + 2 O2 A. Infrared, chlorine atomsB. Ultraviolet, chlorine atomsC. Infrared, chlorine monoxideD. Ultraviolet, chlorine monoxideE. Ultraviolet, CFCl3

Problem

The steady-state stratospheric ozone concentration, which is determined by a balance between photochemical production and dissociation, has been offset by the presence of long-lived chlorofluorocarbons (CFCs) released in the troposphere through anthropogenic activity. According to the following mechanism, ozone depletion requires ________ radiation to initiate a chain reaction in which ________ serves as the catalyst.

CFCl3 + hν → CFCl2• + Cl•

Cl• + O3 → ClO• + O2

ClO•+ O3 → Cl• + 2 O2

 

A. Infrared, chlorine atoms

B. Ultraviolet, chlorine atoms

C. Infrared, chlorine monoxide

D. Ultraviolet, chlorine monoxide

E. Ultraviolet, CFCl3

Solution

We’re being asked to determine the required radiation and the catalyst to initiate the ozone depletion chain reaction.


Given mechanism:

CFCl3 + hν → CFCl2 + Cl
Cl + O3 → ClO + O2
ClO
 + O3 → Cl + 2 O2


We’re starting out with the compound CFCl3 and Let’s see what happens during ozone depletion:

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