The gaseous envelope around the earth is known as atmosphere. The region lying between an altitudes of 11 - 50 km is __________.

(a)

Troposphere

(b)

Mesosphere

(c)

Thermosphere

(d)

stratosphere

The pH of normal rain water is ________

(a)

6.5

(b)

7.5

(c)

5.6

(d)

4.6

Identify the wrong statement in the following __________.

(a)

The clean water would have a BOD value of more than 5 ppm

(b)

Greenhouse effect is also called as Global warming

(c)

Minute solid particles in air is known as particulate pollutants

(d)

Biosphere is the protective blanket of gases surrounding the earth

Release of oxides of nitrogen and hydrocarbons into the atmosphere by motor vehicles is prevented by using __________.

(a)

grit chamber

(b)

scrubbers

(c)

trickling filters

(d)

catalytic convertors

Match the List I with List II and select the correct answer using the code given below the lists.

List I	List II
A. Depletion of ozone layer	1. CO2
B. Acid rain	2. NO
C. Photochemical smog	3. SO2
D. Green house effect	4. CFC

(a)

A	B	C	D
3	4	1	2

(b)

A	B	C	D
2	1	4	3

(c)

A	B	C	D
4	3	2	1

(d)

A	B	C	D
2	4	1	3

Assertion (A) : If BOD level of water in a reservoir is more than 5 ppm it is highly polluted
Reason(R) : High biological oxygen demand means high activity of bacteria in water
i) Both (A) and R are correct and (R) is the correct explanation of (A)
ii) Both (A) and R are correct and (R) is not the correct explanation of (A)
iii) Both (A) and R are not correct
iv) (A) is correct but( R) is not correct

(a)

Both (A) and R are correct and (R) is the correct explanation of (A)

(b)

Both (A) and R are correct and (R) is not the correct explanation of (A)

(c)

Both (A) and R are not correct

(d)

(A) is correct but( R) is not correct

__________ is responsible for global warming.

(a)

CO₂

(b)

NO₂

(c)

N₂O

(d)

None of these

The pH of acid rain is __________

(a)

Equal to 7

(b)

Less than 5.6

(c)

More than 5.6

(d)

Between 7.0 - 9.0

The pollutants that degrade naturally are called ______ pollution

(a)

Bio-degradable

(b)

Non-biodegradable

(c)

Primary

(d)

Secondary

Pick out the pollutant(s) that causes eye irritation __________

(a)

CO₂

(b)

NO₂

(c)

SO₂

(d)

All of these

Green house gases cause _____________

(a)

Increase in temperature of atmosphere

(b)

Prevents global warming

(c)

Trap UV rays

(d)

All the above

Statement I : Global warming is due to Green house effect.
Statement II : Green house gas is CH4

(a)

Both statement I and statement II are true and statement II explains statement I

(b)

Both statement I and statement II are true but statement II does not explain statement I

(c)

Statement I is true but statement II is false

(d)

Both statement I and II are false

The pollutants of troposphere contain ____________

(a)

Dust

(b)

Water Vapours

(c)

Mist

(d)

All of these

Photochemical smog actually causes __________

(a)

Soil pollution

(b)

Noise pollution

(c)

Water pollution

(d)

Air pollution

In Antartica, ozone layer depletion is due to the formation of ______________

(a)

Peroxy acetyl nitrate

(b)

Acrolein

(c)

Chlorine nitrate

(d)

SO₂ and SO₃

Statement I : Photochemical smog is also known as oxidizing smog.
Statement II : Photochemical smog .is chiefly composed of O₃, PAN, etc

(a)

Both statement I and statement II are true and statement II explains statement I

(b)

Both statement I and statement If are true but statement II does not explain statement I

(c)

Statement Lis true but statement II is false

(d)

Both statement I and II are false

Which causes water pollution?

(a)

Jet planes

(b)

Herbicides

(c)

Smoke

(d)

Combustion of fossils

Cause of eutrophication is ____________

(a)

Increase of oxygen in water bodies

(b)

Increase in number of aquatic organisms

(c)

Nutrient enrichment of water bodies

(d)

All ofthese

BOD₅ is _________

(a)

Oxygen used in 5 days

(b)

Waste decomposed in 5 days

(c)

Microorganisms killed in 5 days

(d)

Dissolved oxygen left after 5 days

BOD values less than 5 ppm indicates a water sample to be _________

(a)

Poor in dissolved oxygen

(b)

rich in dissolved oxygen

(c)

Highly polluted

(d)

Not suitable for aquatic life