Question

Which is not a green house gas?
A. Chlorofluorocarbon
B. Methane
C. Carbon dioxide
D. Hydrogen

Answer 1

Carbon dioxide, Methane, Chlorofluorocarbon, sulphur dioxide are the main examples of greenhouse gases, whereas oxygen and hydrogen are not greenhouse gases. These gases cannot leave the internal layer of atmosphere so they get stuck in the environment and cause pollution. These gases produce heat in the environment.

Complete answer:
Greenhouse gases are the components of the atmosphere that cause greenhouse effects. Greenhouse gases absorb infrared radiation and they can trap and hold heat in the atmosphere. By increasing the temperature, greenhouse gases are responsible for the greenhouse effect and it can ultimately lead to global warming. Some greenhouse gases occur naturally but some can rise from human activities. Naturally occurring gases are water vapor, CO$_2$, methane, nitrous oxide, ozone etc; various human activities can increase the levels of these gases.

Hence, the correct answer is option (D).

Additional information:
Since the beginning of the industrial revolution around 1750, the atmospheric concentration of carbon dioxide has been increased by 45% (from 280ppm to 415ppm). Combustion of fossil fuel and natural gas generate the vast majority of anthropogenic carbon dioxide emission. Second biggest methane source is traditional rice cultivation after livestock. Direct radiative effect of a mass of methane and carbon dioxide is 84 times much stronger over a 20- year’s time frame. Greenhouse gases hold some heat energy to keep our planet livable, this process of trapping heat is known as green house effect. Temperature of earth depends on these greenhouse gases, if too low greenhouse gases can make earth too cold while too much greenhouse gases make earth too hot.

Note: Greenhouse gases can be removed from the atmosphere by applying some natural process or negative emissions. Natural processes include condensation and precipitation to remove water vapor from the atmosphere or by chemical reaction.