Question

Which of the following gases is not a greenhouse gas?
(A) $$\text{CO}$$
(B) $${\text{O}}_{\text{2}}$$
(C) $$\text{C}{\text{H}}_4$$
(D) $${\text{H}}_2\text{O}$$ vapour

Answer 1

Hint: In the atmosphere, the greenhouse gas absorbs and emits radiation. This radiation comes within the thermal infrared range. This results in the greenhouse effect.

Complete answer:
You can abbreviate the green-house gas as GHG. Certain human and natural activities increase the concentration of green-house gases in the atmosphere. Earth reflects heat in the form of infra-red radiations. These radiations are trapped by the green-house gases. Due to this, the temperature of earth increases and this causes heating of the atmosphere. You can call this phenomenon global warming. The main cause for global warming is the green-house effect. To control global warming, you should limit the emission of green-house gases. To reduce emission of green-house gases, you should use less heat. You should also reduce usage of air conditioners. You should also replace light bulbs, buy energy-efficient products. You can use less hot water. Also, tree plantation exercise is a good option to control emission of green-house gases and global warming.
Some of the green-house gases are carbon dioxide, methane, water vapour, nitrous oxide, chlorofluorocarbons and ozone. Carbon monoxide, CO is not a greenhouse gas.

Hence, the correct option is the option (A).

Note: Green-house gases do not absorb sunlight. These gases are transparent to sunlight. Green-house gases absorb infra-red light. Then these gases re-emit infrared radiation. But the wavelength of emitted infrared radiation is longer than that of absorbed radiation.