Which of the following does not contribute to the greenhouse effect?
(A) Carbon dioxide
(B) Carbon monoxide
(C) Chloro-fluoro carbon and Methane
(D) Refrigerant freon

Answer Verified Verified
Hint: It is a brand name comprising a series of chemical compounds that cool down or transform hot air to cold air.

Complete answer: The atmosphere of earth is made up of a number of gases. Nitrogen and oxygen make up most of the atmosphere. There are some other gases also that are present in small amounts. Some of these gases trap the heat of the sun. They do not allow the heat to escape back into space. This increases the temperature of the earth. This effect is said to be a greenhouse effect. The gases that are responsible for the greenhouse effect are known as greenhouse gases.

Now lets us find the solution from the given options-
1. Carbon dioxide produced whenever coal, oil, natural gas, and other fossil carbon-rich fuels are burned. While carbon dioxide is not the strong greenhouse gas but it is the biggest contributor to climate change. To minimise emissions of carbon dioxide we need to reduce the use of fuel in our homes and lives.
2. Carbon monoxide is not a primary greenhouse gas. It contributes in a relatively small way directly to the greenhouse effect. Carbon monoxide is a powerful greenhouse gas indirectly. It interacts to produce new greenhouse gases with other molecules in the air.
3. Chlorofluorocarbons, also known as CFCs, are composed of chlorine, fluorine, and carbon compounds. Due to their destructive reaction with O-zone particles, which provide the Earth with a protective layer against UV radiation, CFCs are particularly harmful when released into the air.
Methane is caused by plant matter decomposition, and is released from landfills, swamps, rice paddies. Cattle release methane, as well. Even though methane emissions are lesser than carbon dioxide emissions, it is said as the main greenhouse gas, as each methane molecule has 25 times the carbon dioxide molecule's impact on global warming.
5. Freon is a trademark that uses it on a variety of halocarbon products. They are stable, low toxicity gases or liquids, non-flammable that have been commonly used as refrigerants and as propellants for aerosols.

Thus, the right answer is option D i.e., Refrigerant freon

Note: Greenhouse effect is a warming of the Earth's surface and troposphere, i.e., the lowest atmospheric layer. Greenhouse effect is caused by the presence of water vapour, methane, carbon dioxide, and some other air gases. Water vapour has the biggest effect.
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