Which of the following are greenhouse gases? (A) Carbon dioxide (B) Nitrogen…
2022
Which of the following are greenhouse gases?
(A) Carbon dioxide
(B) Nitrogen dioxide
(C) Methane
(D) Chlorofluorocarbons
(E) Benzene
Choose the correct answer from the options given below:
Answer: C. A, C and D only — ConceptA greenhouse gas absorbs and re-emits outgoing infrared radiation, thereby retaining heat in the lower atmosphere. The classification depends on this…
- A.
A, B and C only
- B.
A, B, C and D only
- C.
A, C and D only
- D.
C, D and E only
Attempted by 1 students.
Show answer & explanation
Correct answer: C
Concept
A greenhouse gas absorbs and re-emits outgoing infrared radiation, thereby retaining heat in the lower atmosphere.
The classification depends on this radiative behaviour, not merely on whether a substance is an atmospheric pollutant.
Application
Classify each named substance by that criterion:
Substance | Classification | Reason |
|---|---|---|
Carbon dioxide | Greenhouse gas | It absorbs infrared radiation and is a major long-lived contributor to warming. |
Nitrogen dioxide | Air pollutant, not normally listed as a greenhouse gas | It mainly contributes to smog and ozone formation; it is not part of the standard greenhouse-gas list used here. |
Methane | Greenhouse gas | It strongly absorbs infrared radiation and has substantial warming potential. |
Chlorofluorocarbons | Greenhouse gases | They absorb infrared radiation and also damage stratospheric ozone. |
Benzene | Volatile organic air pollutant, not normally listed as a greenhouse gas | Its primary environmental and health classification is as a toxic volatile organic compound. |
Contrast
The set carbon dioxide, nitrogen dioxide and methane includes nitrogen dioxide, which is not normally in the standard greenhouse-gas list.
The set carbon dioxide, nitrogen dioxide, methane and chlorofluorocarbons again includes nitrogen dioxide.
The set carbon dioxide, methane and chlorofluorocarbons contains only substances classified here as greenhouse gases.
The set methane, chlorofluorocarbons and benzene includes benzene, a volatile organic air pollutant rather than a standard greenhouse gas.
Result
Therefore, the required set is carbon dioxide, methane and chlorofluorocarbons.