Effects of Ozone Layer Depletion

Q. The statement that is not true about ozone is:

1. It is a toxic gas and its reaction with $NO$ gives $N{O}_2$
2. in the stratosphere, it forms a protective shield against UV radiation.
3. in the atmosphere, it is depleted by CFCs.
4. in the stratosphere, CFCs release chlorine free radicals $\left(Cl\right)$ which reacts with $O_3$ to give chlorine dioxide radicals.

Q. Which one of the following statements is not true?

1. Clean water should have a BOD value of less than 5 ppm.
2. Concentration of the DO below 6 ppm is good for the growth of fishes
3. pH of the drinking water should be between 5.5−9.5
4. Oxides of sulphur, nitrogen, and carbon are the most widespread air pollutants.

Q.

Name a chemical which causes ozone depletion.

Q. Consider the following observations:
(I) The $pH$ of rain water is $5.6$.
(II) The amount of $C{O}_2$ in the atmosphere is 0.03%.
(III) The biochemical oxygen demand is $10ppm$.
(IV) Eutrophication.
A polluted environment is observed under:

1. Both I and IV
2. Both I and III
3. Both III and IV
4. I, III, and IV

Q. Ozone in stratosphere is depleted by:

(AIIMS 2004)

1. $C_6{H}_6{C}_{l6}$
2. $C{F}_{2}C{l}_2$
3. $C_7{F}_{16}$
4. $C_6{F}_6$

Q.

Which of the followings is incorrect about photochemical smog –

1. It is oxidizing in nature.

2. It is formed in stratosphere.

3. It is produced in warm, dry and sunny climate

4. Ozone gas is one of its constituents.

Q. The release of chlorofluorocarbons by the use of refrigerators, air conditioners, deodorants, etc., are destroying the ________ layer of the atmosphere.

1. Ionosphere
2. Mesosphere
3. Humidity
4. Ozone

Q. Assertion :Chlorine sinks are formed during summer, hence, preventing ozone depletion. Reason: In summer season, nitrogen dioxide and methane react with chlorine monoxide and chlorine radicals.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q.

$C\stackrel{.}{l}+O_3\to Cl\stackrel{.}{O}+O_2\left(g\right)$ this reaction is the cause for

1. Classical smog

2. Acid rain

3. Ozone hole

4. Water pollution

Q. The ozone layer absorbs __________ and protects the living beings of the earth.

1. water vapour
2. infrared rays
3. light
4. ultraviolet rays

Q.

Which of the following is incorrect?

1. Greenhouse effect is responsible for global warming

2. Ozone layer does not permit infrared radiation from the sun to reach the earth

3. Acid rains is mostly because of oxides of nitrogen and sulphur

4. Chlorofluorocarbons are responsible for ozone layer depletion

Q. Which of the following does not decompose water?

1. $Mg$
2. $Sr$
3. $Ca$
4. $Be$

Q. Identify the wrong statement:

1. Chlorofluorocarbons are responsible for the ozone layer depletion
2. Green house effect is responsible for global warming
3. Acid rain is caused mostly because of the oxides of nitrogen and sulphur
4. Ozone layer does not permit infrared radiation from the sun to reach the earth

Q. Assertion :In free-radical chlorination reaction using $UV-light,$UV-light is required only for initiation reaction as $Cl-Cl+UV\to 2C{l}^{\ast }$ Initiation Although free radicals are not consumed in overall propagation step and therefore, it appears that the reaction would continue to occur even in absence of $UV$ source once initiated, continuous UV-bathing is required. Reason: Free radicals are consumed in termination step, therefore needs to be produced continuously.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q. Where is ozone layer is situated?

1. Stratosphere
2. Lithosphere
3. Toposphere
4. none of these

Q. Water containing more than 2% of dissolved salts and unfit for human consumption is saline water.

1. True
2. False

Q. Ozone reacts with $H_2{O}_2$ to give oxygen. One volume of ozone gives:

1. one volume of oxygen
2. half volume of oxygen
3. three volumes of oxygen
4. two volumes of oxygen

Q. Ozone hole refers to –

1. Hole in ozone layer
2. Reduction in the thickness of ozone layer in troposphere
3. Increased concentration of ozone
4. Reduction in the thickness of ozone layer in stratosphere

Q. Explain the reaction of the following with ozone-

Q.

Is stratospheric ozone depletion uniform over the earth’s surface?

Q. X is a brown gas. It reacts with sunlight to form gas Y and free oxygen atom. Free oxygen atom reacts with $O_2\left(g\right)$ gives ozone. Gas Y reacts with this ozone gives X again. X and Y are respectively

1. $N_2{O}_5$ and $NO$
2. $N{O}_2$ and $NO$
3. $NO$ and $N{O}_2$
4. $NO$ and $N_{2}O$