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 Which of the following is a set of green house gases ?
Option: 1 CH4, O3, N2, SO2
Option: 2 O3, N2, CO2, NO2
Option: 3  O3, NO2, SO2, Cl2
Option: 4  CO2, CH4, N2O, O3  
 

CO2?,CH4?,N2?O and O3? are the green house gases. This gases are responsible for global warming. For example, carbon dioxide which is emitted from vehicles, factories etc. are mainly responsible green house gas. 

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Posted by

vishal kumar

The presence of soluble fluoride ion up to 1ppm concentration in drinking water is 
 
Option: 1 Harmful to skin
Option: 2 Harmful to bone
Option: 3 Harmful to teeth  
Option: 4 Safe for teeth

Fluoride ion concentration upto 1 ppm is safe for teeth.

Therefore, Option(4) is correct.

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Posted by

Kuldeep Maurya

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The condition that indicates a polluted environment is :  
Option: 1 eutrophication
Option: 2 0.03% of CO2 in the atmosphere
Option: 3 BOD value of 5 ppm
Option: 4 pH of rain water to be 5.6

In Eutrophication nutrient-enriched water bodies support a dense plant population, which kills animal life by depriving it of oxygen and results in subsequent loss of biodiversity. It indicates a polluted environment.

Therefore, the correct option is (1).

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Posted by

Kuldeep Maurya

Reducing smog is a mixture of :
 
Option: 1 Smoke, fog and CH_{2}=CH-CHO
Option: 2 Smoke, fog and O_{3}
Option: 3 Smoke, fog and N_{2}O_{3}  
Option: 4 Smoke, fog and SO_{2}

Reducing or classical smog is the combination of smoke, fog, and SO2 .

Therefore, the Correct option is (4).

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Posted by

Kuldeep Maurya

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The type of pollution that gets increased during the day time and in the presence of O3 is :
   
Option: 1 Reducing smog
Option: 2 Global warming
Option: 3 Oxidising smog  
Option: 4 Acid rain

Global warming 

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Posted by

Ruchiya

The green house gas/es is (are): A. carbon dioxide B. oxygen C. water vapour D. methane Choose the most appropriate answer from the options given below :
Option: 1 A and B only
Option: 2 A and C only
Option: 3 A,C, and D only
Option: 4 A only

The greenhouse gases are CO2, CH4 & H2O vapor.

So, (A), (C) and (D) only is correct.

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Posted by

Kuldeep Maurya

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BOD values (in ppm) for clean water (A) and polluted water (B) are expected respectively as :
Option: 1 \mathrm{A}<5, \mathrm{~B}>17
Option: 2 A>50, B<27
Option: 3 \mathrm{A}>15, \mathrm{~B}>47
Option: 4 A>25, B<17

As we have learnt, 

BOD value for clean water is  < 5 ppm while that for polluted water is  > 17ppm

Hence, the correct answer is option (1)

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Posted by

sudhir.kumar

In stratosphere most of the ozone formation is assisted by:
Option: 1 \mathrm{\gamma-rays}
Option: 2 \mathrm{Cosmic\ rays}
Option: 3 \mathrm{Visible \: radiations}
Option: 4 \mathrm{Ultraviolet \: radiation}

Ozone in the stratosphere is a product of UV radiations acting on dioxygen molecules. These radiations split \mathrm{O_{2}} molecule into \mathrm{O} atoms. These free \mathrm{O} atoms thus formed combine with molecular oxygen to form ozone.

\text{O}_{2}\overset{\text{UV}}{\longrightarrow} 2\; \text{O}\; \text{(g)}

\text{O (g)}+\text{O}_{2} \text{(g)}\rightleftharpoons \text{O}_{3}\; \text{(g)}

Hence the correct answer is option (4)

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Posted by

sudhir.kumar

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Water sample is called cleanest on the basis of which one of the BOD values given below :
Option: 1 11 ppm
Option: 2 15 ppm
Option: 3 3 ppm
Option: 4 21 ppm

As we have learnt,

Lesser the BOD value, lesser is the pollution and cleaner is the water sample.

Therefore, the water sample having 3 ppm BOD value is the cleanest among the given ones.

Hence, the correct answer is Option (3)

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Posted by

sudhir.kumar

The deposition of X$ and $Y on ground surfaces is referred as wet and dry depositions, respectively. X$ and $Y are :
Option: 1 \begin{array}{ll} \mathrm{X}=\mathrm{CO}_{2} & ,\mathrm{Y}=\mathrm{SO}_{2} \\ \end{array}
Option: 2 \mathrm{X}=\text { Ammonium salts , } \mathrm{Y}=\mathrm{SO}_{2}
Option: 3 \mathrm{X}=\text { Ammonium salts , } \mathrm{Y}=\mathrm{CO}_{2}
Option: 4 \mathrm{X}=\mathrm{SO}_{2} \: \: , \mathrm{Y}=\text { Ammonium salts }

Aerosol particles of ammonium salts in rain drops lead to wet deposition.

\mathrm{SO_{2}} is absorbed directly on both solid and liquid and this lead to dry deposiion

Hence the correct answer is option (2)

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Posted by

sudhir.kumar

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