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Difficulty: HardGreenhouse Effect, Global Warming, and Ozone Layer Depletion

Carbon(IV) oxide (CO2\text{CO}_2) drives global warming primarily by absorbing high-energy solar ultraviolet radiation in the troposphere, whereas chlorofluorocarbons (CFCs\text{CFCs}) destroy stratospheric ozone by absorbing long-wave infrared radiation emitted from the Earth's surface.

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Answer

The statement is false. Carbon(IV) oxide (CO2\text{CO}_2) traps heat by absorbing outgoing terrestrial infrared (thermal) radiation, not incoming solar ultraviolet radiation. Meanwhile, chlorofluorocarbons (CFCs\text{CFCs}) cause ozone depletion when high-energy solar ultraviolet photolysis releases reactive chlorine free radicals (Cl∙\text{Cl}^\bullet) in the stratosphere.
The statement is false because it reverses the radiation types and chemical mechanisms involved in global warming and ozone depletion. Carbon(IV) oxide (CO2\text{CO}_2) traps terrestrial long-wave infrared radiation in the troposphere to produce the greenhouse effect. In contrast, ozone depletion by chlorofluorocarbons (CFCs\text{CFCs}) occurs in the stratosphere via the photolytic generation of chlorine free radicals (Cl∙\text{Cl}^\bullet) induced by high-energy solar ultraviolet radiation.

Step-by-Step Solution

1
Analyze the mechanism and type of electromagnetic radiation associated with the greenhouse effect and global warming.
Greenhouse gases such as CO2\text{CO}_2, CH4\text{CH}_4, and N2O\text{N}_2\text{O} allow short-wave solar radiation to pass through the atmosphere but absorb long-wave infrared (heat) radiation re-emitted by the Earth's surface.
Trapping terrestrial infrared radiation in the troposphere causes atmospheric warming.
2
Analyze the mechanism and type of electromagnetic radiation associated with ozone layer depletion.
Chlorofluorocarbons (CFCs\text{CFCs}) in the stratosphere absorb high-energy ultraviolet (UV) radiation, leading to homolytic fission of C−Cl\text{C}-\text{Cl} bonds: CF2Cl2→hνCF2Cl∙+Cl∙\text{CF}_2\text{Cl}_2 \xrightarrow{h\nu} \text{CF}_2\text{Cl}^\bullet + \text{Cl}^\bullet. The resulting chlorine radical initiates catalytic ozone breakdown (Cl∙+O3→ClO∙+O2\text{Cl}^\bullet + \text{O}_3 \rightarrow \text{ClO}^\bullet + \text{O}_2).
Ozone depletion is a photolytic radical-catalyzed chemical process triggered by solar UV light, not an infrared heat absorption phenomenon.
3
Compare the statement's claims against the established chemical mechanisms.
The statement incorrectly attributes UV absorption to CO2\text{CO}_2's greenhouse mechanism and IR absorption to CFCs\text{CFCs}' ozone destruction mechanism.
Both radiation types and underlying physical/chemical mechanisms are interchanged.

Key Concept

Mechanistic Distinction Between the Greenhouse Effect (Infrared Trapping) and Stratospheric Ozone Depletion (Ultraviolet Photolysis)
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Topics

Greenhouse Effect, Global Warming, and Ozone Layer Depletion

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