Tag: causes of greenhouse effect

Questions Related to causes of greenhouse effect

What gases are involved in ozone depletion?

  1. Nitrogen

  2. Chlorine and Bromine

  3. Chlorofluorocarbons (CFCs) and Ozone Depleting Substances (ODS)

  4. Both B and C


Correct Option: B

What causes effects of ozone layer?

  1. Alpha Radiations

  2. Ultraviolet Radiations

  3. Gamma radiations

  4. Beta Radiations


Correct Option: B

'HCFCs' can be used in refrigerants instead of

  1. $CO _{2}$

  2. Chlorine

  3. CFCs

  4. $O _{2}$


Correct Option: C

HCs are thermodynamically not stable towards

  1. Acidification

  2. Decomposition

  3. Reduction

  4. Oxidation


Correct Option: D

Which among the following alkane has largely replaced the ozone layer-depleting halomethanes in household refrigerators and freezers?

  1. Methane

  2. Propane

  3. Butane

  4. Ethane


Correct Option: C

Ozone depletion is occurring due to 

  1. PCB

  2. CO

  3. PAN

  4. None of the above


Correct Option: D
Explanation:

Ozone is the protective layer present in the stratosphere. The harmful ultraviolet radiation is absorbed by the ozone layer. They are carried high into the stratosphere by wind action. Depletion begins when CFC’s get into the stratosphere. Ultraviolet radiation from the sun breaks up these CFCs. The breaking up action releases chlorine atoms. Chlorine atoms react with ozone, starting a chemical cycle that destroys the good ozone in that area. It is not depleted by PCB, carbon monoxides, and PAN. 

Therefore, the correct answer is option D.

The major pollutants to deplete ozone are

  1. Chlorofluorocarbons

  2. Nitrogen oxides

  3. Hydrocarbons

  4. All of the above


Correct Option: A
Explanation:

Pollution leads to the addition of harmful components in the environment which adversely affect the quality of the environment. CFCs is an organic compound and a volatile derivative of methane, ethane, and propane. It is known as Freon. They are used as a refrigerant. The radical chlorine escapes from CFC in the presence of UV radiation and is long lived in the upper atmosphere where it catalyzes the conversion of ozone into oxygen molecule.

So, the correct answer is option A.

Ozone layer of upper atmosphere is being destroyed by 

  1. Sulphurdioxide

  2. Carbondioxide

  3. Chlorofluorocarbon

  4. Smog


Correct Option: C
Explanation:
CFCs are used as refrigerants in refrigerators and AC. CFCs discharged in the lower part of atmosphere move upward and reach the stratosphere. In the stratosphere, UV rays act on them releasing Cl atoms. Cl reduces the ozone and releases molecular oxygen, Cl atoms are not consumed in the reaction. Hence, whatever CFCs are added to the stratosphere, they have permanent and continuing effects on ozone levels. This has resulted in the formation of a large area of thinned ozone layer, commonly called as the ozone hole.

Ozone protects biosphere from high energy

  1. Infra-red rays

  2. Ultraviolet rays

  3. X - rays

  4. Gamma rays


Correct Option: B
Explanation:

The ozone layer is mainly found in the stratosphere. Ozone layer acts as a shield that absorbs ultraviolet radiation from the sun. UV rays are highly injurious to living organisms since DNA and proteins of living organisms preferentially absorb UV rays, and its high energy breaks the chemical bonds within these molecules. UV-B damages DNA and mutation may occur. It causes aging of the skin, damage to skin cells and various types of skin cancers.

Chlorofluorocarbon releases a chemical harmful to ozone

  1. Fluorine

  2. Sulphur dioxide

  3. Nitrogen peroxide

  4. Chlorine


Correct Option: D
Explanation:

Ozone gas is a layer which is present in the stratosphere and absorbs the harmful ultraviolet radiation. The ozone depletion takes due to the excessive emission of (CFCs). CFC find wide use as refrigerants. CFCs discharged in the lower part of atmosphere move upward and reach stratosphere. In stratosphere, UV rays act on them releasing Cl atoms. Cl degrades ozone releasing molecular oxygen, with these atoms acting merely as catalysts; Cl atoms are not consumed in the reaction. Hence, whatever CFCs are added to the stratosphere, they have permanent and continuing affects on ozone levels. This has resulted in formation of a large area of thinned ozone layer, commonly called as the ozone hole.

Therefore, the correct answer is option D.