MCQ Questions for Class 11 Medical Chemistry Environmental Chemistry Quiz 9

Pollution can be controlled by :

0%
Sewage treatment
0%
Checking atomic blasts
0%
Manufacturing electrically operated vehicles
0%
All the above

Phenomenon of 'industrial melanism' demonstrates:

0%
Geographical isolation
0%
Reproduction isolation
0%
Natural selection
0%
Induced mutation

Long term usage of insecticides results in

0%
Sensitivity in insects
0%
Kills insects
0%
Resistance in insect
0%
Decrease in insect population

Which harmful radiations are absorbed by ozen layer?

0%
UV
0%
X-RAY
0%
Visible light
0%
Gamma rays

Explanation

The ozone layer or ozone( $O_3$ ) shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet(UV)radiation.
Overexposure to UV radiation may cause skin cancer, damage of the eye and the suppression of the immune system.
Hence The harmful radiations are absorbed by ozone layer UV.
So, the correct answer is 'UV'.

What will happen if chemical fertilizers are used for a longer time.

0%
soil always stays fertile for plant growth
0%
soil fertility is damaged
0%
soil stops responding to fertilizers
0%
soil health is maintained

Identify the incorrect statement from the following

0%
Oxides of nitrogen in the atmosphere can cause the depletion of ozone layer
0%
Ozone absorbs the intense ultraviolet radiations of the sun
0%
Depletion of ozone layer is because of its chemical reactions with CFC
0%
Ozone absorbs infrared radiations

In the upper layers of atmosphere, ozone is formed ?

0%
By action of electric discharge on oxygen molecules
0%
By action of ultraviolet rays on oxygen molecules
0%
By action of infrared rays on oxygen molecules
0%
Due to sudden drop of pressure

Explanation

In the upper layer of atmosphere, the Ultraviolet rays (UV rays) split the molecule of oxygen $(O_2)$ into its constituent 2 atoms.
Each of the atom then combine with another oxygen $(O_2)$ molecule which gives rise to Ozone $(O_3)$ .
Hence option B is correct answer.

Why ozone is known as 'chemical weed ' ?

0%
Because it is formed by chemical reactions
0%
Because it is harmful as well useful
0%
Because it is harmful, just like weeds for mankind
0%
Ozone is not designated as chemical weed

Water filled in two glasses

$A$ and

$B$ have

$BOD$ values of

$10$ and

$20$ , respectively. The correct
statement regarding them, is:

0%
$A$ is more polluted than $B$
0%
$A$ is suitable for drinking, whereas $B$ is not
0%
$B$ is more polluted than $A$
0%
Both $A$ and $B$ are suitable for drinking

Explanation

Two glasses "

$A$ " and "

$B$ " have

$BOD$ values

$10$ and "

$20$ ", respectively.
Hence glasses "

$B$ " is more polluted than glasses "

$A$ ".

Ozone hole over Antarctica appear during

0%
Spring
0%
Autumn
0%
Summer
0%
Winter

500 ml of a sample COD of water required 19.6 mg of

$K_2Cr_2O_7$ of water sample is?

0%
9 PPM
0%
8PPM
0%
16.8 PPM
0%
10 PPM

Biochemical Oxygen Demand (BOD) value can be a measure of water pollution caused by the organic matter. Which of the following statement is correct ?

0%
Aerobic bacteria decrease the BOD value.
0%
Anaerobic bacteria increase the BOD value.
0%
Clean water has BOD value higher than 10 ppm.
0%
polluted water has BOD value higher

Water samples with

$BOD$ values of

$4 ppm$ and

$18 ppm$ , respectively, are:

0%
highly polluted and clean
0%
highly polluted and highly polluted
0%
clean and highly polluted
0%
clean and clean

Explanation

Clean water would have

$BOD$ value of less than

$5\ ppm$ whereas highly polluted water could have a

$BOD$ value of

$17\ ppm$ or more.

The atmosphere between the heights

$10$ to

$50$ kilometer above the sea level is :

0%
troposphere
0%
stratosphere
0%
mesosphere
0%
ionosphere

Explanation

Solution:- (B) Stratosphere

Stratosphere lies between

$10$ to

$50$ Km. from sea level.

The concentration of dissolved oxygen (DO) in cold water can go upto :

0%
10 ppm
0%
14 ppm
0%
16 ppm
0%
8 ppm

All except which cause pollution:

0%
thermal power plant
0%
hydro - electric plant
0%
nuclear power plant
0%
automobiles

Which of these gases is an atmospheric pollutant?
1 carbon monoxide
2 nitrogen dioxide
3 sulfur dioxide.

0%
$1$ only
0%
$2$ only
0%
$3$ only
0%
$1, 2$ and $3$

Explanation

Solution:- (D)

$1, \; 2$ and

$3$

These all gases are atmospheric pollutants as all lead to air pollution.

coz of

Nitrogen dioxide (NO2), sulfur dioxide (SO2), and carbon monoxide are important ambient air pollutants. High-intensity, confined space exposure to NO2 has caused catastrophic injury to humans, including death. Ambient NO2 exposure may increase the risk of respiratory tract infections through the pollutant's interaction with the immune system. Sulfur dioxide (SO2) contributes to respiratory symptoms in both healthy patients and those with underlying pulmonary disease. Controlled human exposure studies have demonstrated that experimental SO2 exposure causes changes in airway physiology, including increased airways resistance. Both acute and chronic exposure to carbon monoxide are associated with increased risk for adverse cardiopulmonary events, including death. However, studies have not demonstrated a clear dose-dependent health risk response to increasing amounts of these pollutants except at high concentrations. In addition, a number of studies examining the effects of ambient level exposure to NO2, SO2, and CO have failed to find associations with adverse health outcomes.

Which of the following practices will not come under green chemistry?

0%
If possible making use of soap made of vegetable oils instead of using synthetic detergents
0%
Using $H_{2} O_{2}$ for bleaching purpose instead of using chlorine based bleaching agents
0%
using bicycle for travelling small distance instead of using petrol / diesel based vehicles
0%
Using plastic cans for neatly storing substance

Which of the following conditions shows the polluted environment ?

0%
pH of rain water is $5 . 6$
0%
amount of carbondioxide in the atmosphere is $0.03 %$
0%
biochemical oxygen demand 10 ppm .
0%
eutrophicition

Chlorine atoms in the upper atmosphere cause the breakdown of ozone.

$Cl+O_3\rightarrow O_2+ClO$

$ClO+O\rightarrow Cl+O_2$
Which statements about these chlorine atoms are correct?

$1$ . The chlorine atoms act as catalysts.

$2$ . The chlorine atoms are free radicals.

$3$ . The chlorine atoms are formed by heterolytic fission of a covalent bond in chlorofluorocarbons.

0%
$1, 2$ and $3$ are correct
0%
$1$ and $2$ only are correct
0%
$2$ and $3$ only are correct
0%
$1$ only is correct

Chlorine atoms in the upper atmosphere cause the breakdown of ozone.

$Cl+O_3\rightarrow O_2+ClO$

$ClO+O\rightarrow Cl+O_2$
Which statements are correct when referring to these chlorine atoms?

$1$ . The chlorine atoms act as catalysts.

$2$ . The chlorine atoms are free radicals.

$3$ . The chlorine atoms are formed by heterolytic fission of a covalent bond in chlorofluorocarbons.

0%
$1, 2$ and $3$ are correct
0%
$1$ and $2$ only are correct
0%
$2$ and $3$ only are correct
0%
$1$ only is correct

Explanation

In the given reaction, i.e., decomposition of ozone, the chlorine atoms are free radicals and acts as catalysts.

Chlorine initiates the breakdown of ozone and combines with a freed oxygen to create two oxygen molecules.

Hence only

$1$ and

$2$ are correct.

Antiknocking agent used for unleaded gasoline is:

0%
$BXT$
0%
$TBA$
0%
$MTBE$
0%
all of these

Which one is not the correct statement?

Pollution means:

0%
the presence of anything in the environment in excess of required limit
0%
anything put into the environment which was not there in its natural state.
0%
direct or indirect changes in one or more components of the ecosystem which are not harmful to living organisms
0%
international release of any chemical substance in the environment with harmful effects

Carbon monoxide,

$CO$ , nitrogen dioxide,

$NO_{2}$ , and sulfur dioxide,

$SO_{2}$ , are all atmospheric
pollutants.
Which reaction concerning these compounds occurs in the atmosphere?

0%
$CO$ is spontaneously oxidised to $CO_{2}$
0%
$NO_{2}$ is reduced to $NO$ by $CO$
0%
$NO_{2}$ is reduced to $NO$ by $SO_{2}$
0%
$SO_{2}$ is oxidised to $SO_{3}$ by $CO_{2}$

Explanation

$N{O}_{2}$ is reduced by

$S{O}_{2}$ to

$NO$ , i.e.,

$N{O}_{2} + S{O}_{2} \longrightarrow NO + S{O}_{3}$

Which pair of compounds would make an NPK fertiliser?

0%
Ammonium sulfate and potassium phosphate
0%
Calcium hydroxide and ammonium nitrate
0%
Calcium phosphate and potassium chloride
0%
Palcium phosphate and potassium chloride

The knocking will be maximum when the mixture of the fuel is

0%
straight-chain
0%
iso-chain
0%
neo-chain
0%
none of these

Which of the following substance is used as an anti nock compound?

0%
TEL
0%
Lead tetrachloride
0%
Lead acetate
0%
$\mathrm{ C_{2}H_{5}PbCl}$

If BOD of river is high, it means that the river is:

0%
not polluted
0%
very much polluted with inorganic chemicals
0%
very much polluted with organic chemicals which are decomposed by micro- organisms
0%
polluted with pesticides

Pollution can be controlled if :

0%
all automobiles must be fitted with exhaust system's catalytic converters
0%
use of fossil fuels must be minimised and non-conventional energy sources should be developed
0%
emphasis on green chemistry is given
0%
population is stabilised

When huge amount of sewage is dumped in a river, the BOD will:

0%
increase
0%
remain unchanged
0%
decrease
0%
increase or decrease

The following reactions occur in the stratosphere:

0%
$O_2 +UV \to O+O$
0%
$O_2 +O \to O_3$
0%
$Cl +O_3 \to ClO+O_2$
0%
$SO_3 +H_2O \to H_2SO_4$

Explanation

In the stratosphere, ultraviolet light reacts with

$O_2$ molecules to form atomic oxygen. Atomic oxygen then reacts with an

$O_2$ molecule to produce ozone (

$O_3$ ). As a result of this reaction, the stratosphere contains an appreciable concentration of ozone molecules that constitutes the ozone layer.

Volatile organic compounds that contain chlorine and fluorine, which are known as chlorofluorocarbons (CFCs), are capable of reaching the stratosphere, where they can react with ultraviolet light to generate chlorine atoms and other chlorine-containing species that catalyze the conversion of ozone to

$O_2$ , thereby decreasing the amount of

$O_3$ in the stratosphere.

Pollutant is a chemical substance or factor which disturbs:

0%
our balanced environment
0%
geochemical cycles
0%
flora of any region
0%
fauna of any region

Explanation

Chemical pollution introduces chemicals into the natural environment, negatively affecting the air, water, and soil. Such pollutants can come from a wide variety of sources. When chemical pollutants are concentrated in an area for a period, they can adversely affect the ecosystem and those who live in the area.

$\mathbf{Hence\ the\ correct\ answer\ is\ option\ (A)}.$

Most important cause of soil pollution is :

0%
iron junks
0%
glass junks
0%
detergents
0%
plastics

Which one is not a correct statement? To minimise pollution:

0%
manures and biofertilizers should be used in place of chemical fertilizers
0%
all nuclear tests must be stopped
0%
green belts in cities should be developed
0%
domestic garbage must be burnt

Which statement is not correct?

0%
$CO$ is the main air pollutant
0%
All pollutants are not wastes
0%
Water is polluted by dissolved oxygen
0%
Lichens are pollution indicators

An object is located at a height of

$5\ km$ from the surface of the earth. The object is located in which part of the atmosphere?

0%
Thermosphere
0%
Mesosphere
0%
Stratosphere
0%
Troposphere

The term "water pollution" can be defined in several ways. Which of the following statements does not give the correct definition?

0%
The addition of undesirable substances to water bodies
0%
The removal of desirable substances from water bodies
0%
A change in pressure of the water bodies
0%
A change in temperature of the water bodies

Biochemical oxygen demand , (BoD) is a measure of organic material present in water . BoD value less than 5 ppm indicates a water sample to be ...

0%
rich in dissolved oxygen
0%
poor in dissolved oxygen
0%
highly polluted
0%
not suitable for aquatic life

The ozone layer forms natural by ;

0%
the interactions of CFC with oxygen
0%
the interaction of UV radiation with oxygen
0%
the interaction of IR radiation with oxygen
0%
the interaction of oxygen and water vapour

Planting more and more trees helps to :

0%
reduce $CO_{2}$ in the air
0%
increase $CO_{2}$ in the air
0%
reduce $O_{2}$ in the air
0%
reduce $CO_{2}$ and increase $O_{2}$ in the air

Explanation

after planting educe

$CO_{2}$ and increase

$O_{2}$ in the air

The gaseous envelope around the earth is known as atmosphere . The lowest layer of this is extended upto 10 km from sea level, this layer is ...

0%
Stratosphere
0%
Troposphere
0%
Mesosphere
0%
Hydrosphere

Say true or false:
Chlorofluorocarbons deplete the ozone layer in the atmosphere.

0%
True
0%
False

Which of the following statements is correct?

0%
Ozone hole is a hole formed in stratosphere from which ozone out.
0%
Ozone hole is a hole formed in the troposphere from which ozone oozes out
0%
Ozone is hole is tinning of zone layer of stratosphere at some places
0%
Ozone hole means vanishing of zone layer around the earth completely

Which of the following are the main sources of water pollution?

0%
Sewage and domestic wastes
0%
Household detergents that are used for washing purposes
0%
Oil spills
0%
All of these

________ poisons sea life.

0%
Industrial waste
0%
Household detergents
0%
Oil spills
0%
Heavy metals

Assertion :Biocides are effective against animals.

Reason :Algicides are effective against weeds.

0%
If both the assertion and the reason are true and the reason is a correct explanation of the assertion
0%
If both the assertion and reason are true but the reason is not a correct explanation of the assertion
0%
If the assertion is true but the reason is false
0%
If both the assertion and reason are false
0%
If the assertion is false but reason is true

The most likely reason for the development of resistance to pesticides in insects, damaging a crop, is

0%
Direct mutation
0%
Acquired heritable changes
0%
Random mutation
0%
Genetic recombination

Cochineal insects have proved very useful for the control of

0%
Eicchornia
0%
Cactus
0%
Weeds
0%
Parathenium

Regular use of which of the following fertilizers increases the acidity of soil ?

0%
Potassium nitrate
0%
Urea
0%
Superphosphate of lime
0%
Ammonium sulphate

Explanation

Regular use of ammonium sulphate increases the acidity of soil.
The hydrolysis of ammonium sulphate produces sulphuric acid which increases the acidity of soil.

$\displaystyle (NH_4)_2SO_4 \rightarrow 2NH_3 + H_2SO_4$

To prevent acidity, slaked lime is added to neutralize the acid.

Ozonosphere occurs at height of

0%
8-10 km. above poles
0%
8-10 km. above equator
0%
11-16 km above poles
0%
11-16 km above equator

CBSE Questions for Class 11 Medical Chemistry Environmental Chemistry Quiz 9 - MCQExams.com

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Practice Class 11 Medical Chemistry Quiz Questions and Answers

CBSE Questions for Class 11 Medical Chemistry Environmental Chemistry Quiz 9 - MCQExams.com

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Practice Class 11 Medical Chemistry Quiz Questions and Answers

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