Question

One greenhouse gas contributes 14% to total global warming and another contributes 6%. These are respectively identified as
(a) $NO_2$ and $CO_2$
(b) CFC and $N_2O$
(c) Methane and $CO_2$
(d) Methane and CFCs
(e) CFCs and $CO_2$

Answer 1

Hint: The greenhouse effect is the warming of the earth's surface when the infrared radiations from the earth's surface are absorbed and trapped in the earth's atmosphere. The gases responsible for the warming of the atmosphere are called greenhouse gases.

Complete answer:
The greenhouse gas which contributes about 14% to the total global warming is CFC and 6% due to $N_2O$.
The CFC stands for the chlorofluorocarbons. These are any of the several organic compounds composed of carbon, fluorine, and chlorine. CFCs also go by the name of Freons, a trademark of the E.I. du Pont de Nemours & Company. CFCs were originally developed as refrigerants and used in air conditioners as well. The other variants of CFCs are trichlorofluoromethane (CFC- 11) and dichlorodifluoromethane (CFC- 12) . They are also used in aerosol- spray propellants, solvents, and foam blowing agents. They are well suited for other applications because they are non- toxic and nonflammable. When hydrogen is present in place of one or more chlorines, they are called hydro- chlorofluorocarbons, or HCFCs.
Nitrous oxide is an air pollutant released during the burning of fossil fuels and solid waste, agricultural and industrial activities. They come from a group of nitrogen oxides, which is a group of seven gases and compounds composed of nitrogen and oxygen, sometimes collectively known as NOx gases. The common name of nitrous oxide is laughing gas, which is a greenhouse gas that contributes to global warming.
So, the correct answer is, ‘CFC and $N_2O$.’

Note:
- The effect of each greenhouse gas on the climate of the earth depends on its chemical nature and its relative concentration in the atmosphere. Some gases can highly absorb infrared radiation or occur in large quantities, whereas others have a considerably lower potential for absorption or occur only in trace amounts.
- $CO_2$ contributes about 60% while $CH_4$ contributes about 20% towards total global warming.