Tag: stratospheric pollution

Questions Related to stratospheric pollution

Assertion : Ozone is destroyed by CFCs in the upper stratosphere

Reason : Ozone holes increase the amount of UV radiation reaching the earth.

zoology allotropy of oxygen ozone - a case study stratospheric pollution ozone and its depletion

  1. Assertion and reason are correct , but the reasons is not the explanation for the assertion

  2. Assertion is false, but the reason is correct

  3. Assertion and reason are incorrect, Assertion and reason are both correct

  4. And the reason is the correct explanation for the assertion

Show answer
Correct Option: A
Explanation:
The upper stratosphere consists of ozone $(O _3)$, which protect us from harmful ultraviolet (UV) radiations coming from the sun.
When CFC reacts with ozone it breaks the molecule of ozone resulting in ozone layer depletion.

A considerable part of the harmful $UV$ rays of the sum does not reach the surface of the earth. This is because high above the earth's atmosphere, there is a layer of___________.

zoology allotropy of oxygen ozone - a case study stratospheric pollution ozone and its depletion

  1. $O _3$

  2. $CO _2$

  3. $SO _2$

  4. $NO$

Show answer
Correct Option: A
Explanation:

This is because of ozone layer.Ozone is a gas in the atmosphere that protects everything living on the Earth from harmful ultraviolet (UV) rays from the Sun.The ozone layer absorbs ultraviolet (UV) radiation from the sun, preventing most of it from reaching the earth's surface. 

The absorption of $UV$ radiation by $O _3$:

zoology allotropy of oxygen ozone - a case study stratospheric pollution ozone and its depletion

  1. protects the inhabitants of our planet from injurious radiation

  2. maintains an equilibrium between the concentrations of $O _2$ and $O _3$

  3. makes both the function A and B above effective

  4. makes no function effective

Show answer
Correct Option: C
Explanation:

We know that, UV-B radiation is very harmful. 


The UV light will also destroy ozone and break ozone back down into atomic oxygen (O) and diatomic oxygen ($O _2$) Therefore, the ozone layer does a great job filtering UV radiation and this process protects the inhabitants of our planet from injuries radiation and adsorption of UV radiation has maintained the equilibrium between the con. of oxygen and ozone in the atmosphere.


So, A and B are both effective 

C is the correct answer.

Ozone layer is being depleted. This is due to :

zoology allotropy of oxygen ozone - a case study stratospheric pollution ozone and its depletion

  1. NO (Nitrogen oxide) emission from supersonic jets

  2. Chlorofluorocarbon used as aerosols

  3. Both (a) and (b)

  4. None of the above

Show answer
Correct Option: C
Explanation:

Chlorofluorocarbons (CFCs) and other halogenated ozone-depleting substances (ODS) are mainly responsible for ozone depletion.


Depletion of the ozone layer is likely to aggravate existing health effects caused by exposure to UV radiation, as stratospheric ozone is a particularly effective UV radiation absorber. As the ozone layer becomes thinner, the protective filter provided by the atmosphere is progressively reduced. 

Consequently, human beings and the environment are exposed to higher UV radiation levels, and especially higher UV levels that have the greatest impact on human health, animals, marine organisms and plant life.


Hence, option C is correct.

State True or False.
The main function of ozone is to absorb sun's UV radiations, hence protecting the Earth from its harmful effects.

zoology allotropy of oxygen ozone - a case study stratospheric pollution ozone and its depletion

  1. True

  2. False

Show answer
Correct Option: A
Explanation:
True.
The main function of ozone is to absorb Sun's UV radiations, hence protecting the Earth from its harmful effects. The function of the ozone layer is to shield the earth from the harmful ultraviolet rays of the sun and to keep the Earth warm.

Which of the following chemicals is responsible for ozone layer destruction?

zoology allotropy of oxygen ozone - a case study stratospheric pollution ozone and its depletion

  1. Chlorofluorocarbons

  2. Halogens

  3. Hydrofluorocarbons

  4. All of the above

Show answer
Correct Option: D
Explanation:
The chemicals responsible for ozone layer destruction are:

  • Chlorofluorocarbons: Chlorofluorocarbons (CFCs) are non-toxic, non-flammable chemicals containing atoms of carbon, chlorine, and fluorine. They are used in the manufacture of aerosol sprays, blowing agents for foams and packing materials, as solvents, and as refrigerants.

  • Halogens: Ozone is destroyed by reactions with chlorine, bromine, nitrogen, hydrogen, and oxygen gases. Reactions with these gases typically occur through catalytic processes. Because of catalytic reactions, an individual chlorine atom, on an average, can destroy nearly a thousand ozone molecules, before it is converted into a form harmless to ozone.

  • Hydrofluorocarbons: The HFCs are a class of replacements for CFCs and affect the ozone layer. 

The ozone layer is important because it:

zoology allotropy of oxygen ozone - a case study stratospheric pollution ozone and its depletion

  1. is used by living organisms for respiration.

  2. increases the temperature of the earth.

  3. reduces the amount of ultraviolet rays reaching the earth.

  4. reflects the heat from the earth back into the atmosphere.

Show answer
Correct Option: C
Explanation:

The ozone layer is important because it absorbs ultraviolet (UV) radiation from the sun, preventing most of it from reaching the earth's surface. Radiation in the UV spectrum has wavelengths just shorter than those of visible light.

So answer is C.

The ozone layer in our atmosphere protects us from the bad effects of:

zoology allotropy of oxygen ozone - a case study stratospheric pollution ozone and its depletion

  1. Carbon dioxide

  2. CFC's

  3. The sun's ultraviolet rays

  4. All of the above

Show answer
Correct Option: C
Explanation:

The ozone layer acts as a filter for the shorter wavelength and highly hazardous ultraviolet radiation (UVR) from the sun, protecting life on Earth from its potentially harmful effects. When the sky is clear, there is an inverse relationship between stratospheric ozone and solar UVR measured at the Earth’s surface. That is,the lower the ozone levels, the higher the solar UVR.


Hence, the correct option is $\text{C}$

Ozone in stratosphere is depleted by_____________.

zoology allotropy of oxygen ozone - a case study stratospheric pollution ozone and its depletion

  1. $C{ F } _{ 2 }{ Cl } _{ 2 }$

  2. ${ C } _{ 7 }{ H } _{ 16 }$

  3. ${ C } _{ 6 }{ H } _{ 6 }{ Cl } _{ 6 }$

  4. ${ C } _{ 6 }{ F } _{ 6 }$

Show answer
Correct Option: A
Explanation:

Ozone in stratosphere is depleted by chlorofluorocarbon, such as $CF _2Cl _2$.
It is dichlorodifluoromethane also known as freon-12.

Ultraviolet radiation from sunlight causes the reaction that produces:

zoology allotropy of oxygen ozone - a case study stratospheric pollution ozone and its depletion

  1. $SO _2$

  2. CO

  3. Ozone

  4. Fluorides

Show answer
Correct Option: C
Explanation:

Air pollution is formed through the reaction of solar radiation with airborne pollutants like nitrogen oxides and volatile organic compounds. These compounds, which are called primary pollutants, are often introduced into the atmosphere through automobile emissions and industrial processes. Ultraviolet light can split nitrogen dioxide into nitric oxide and monatomic oxygen; this monatomic oxygen can then react with oxygen gas to form ozone. 

Therefore, the correct answer is option C.