Environmental Study Questions in English

(C) According to environmental chemistry data,the primary sources of carbon monoxide $(CO)$ in the atmosphere include incomplete combustion of fuels and natural processes like forest fires. Forest fires contribute approximately $9.5\%$ of the total $CO$ present in the atmosphere.

(D) The greenhouse effect was first proposed by $Jean \ Fourier$ in $1824$.
Later,$Chamberlin$ and $Svante \ Arrhenius$ further developed the theory regarding the role of carbon dioxide in the atmosphere.
Therefore,both $Chamberlin$ and $Svante \ Arrhenius$ are associated with the study of the greenhouse effect.
Thus,the correct option is $D$.

(C) The atmosphere is divided into different layers based on temperature variations.
The troposphere extends from sea level up to about $10 \ km$.
The stratosphere lies above the troposphere and extends from $10 \ km$ to $50 \ km$ above sea level.
Therefore,the correct range is $10$ to $50 \ km$.

(A) The Global Warming Potential $(GWP)$ is a measure of how much heat a greenhouse gas traps in the atmosphere over a specific time period,usually $100$ years,relative to $CO_2$.
The approximate $GWP$ values ($100$-year) are:
$CFCs$ (Chlorofluorocarbons): $\approx 5000 - 10000$
$N_2O$ (Nitrous oxide): $\approx 273 - 298$
$CH_4$ (Methane): $\approx 27 - 30$
$CO_2$ (Carbon dioxide): $1$
Therefore,the correct order is $CFC > N_2O > CH_4 > CO_2$.

(B) According to the data provided in the $NCERT$ textbook for Environmental Chemistry,the percentage contribution of various gases to global warming is as follows:
$CO_2$ contributes $50\%$,$CH_4$ contributes $19\%$,$CFCs$ contribute $14\%$,$O_3$ contributes $12\%$,and $N_2O$ (laughing gas) contributes $4\%$.
Therefore,the correct option is $B$.

(D) The concept of the greenhouse effect was first proposed by the French mathematician and physicist Jean-Baptiste Joseph Fourier in $1824$. He suggested that the Earth's atmosphere acts like a glass cover of a greenhouse,trapping heat and keeping the planet warm.

(D) The depletion of the ozone layer in Antarctica is primarily caused by the formation of chlorine nitrate $(ClONO_2)$ and chlorine monoxide $(ClO)$ radicals.
During the winter,polar stratospheric clouds form,which provide a surface for the reaction of $HCl$ and $ClONO_2$ to produce $Cl_2$.
When sunlight returns in the spring,$Cl_2$ dissociates into chlorine atoms,which catalyze the destruction of ozone $(O_3)$.

(D) Smog is a type of air pollution that contains harmful substances like ozone,nitrogen oxides,and sulfur dioxide.
These pollutants have detrimental effects on various materials.
$1$. Smog causes the cracking of rubber due to the presence of ozone.
$2$. It causes the discoloration and degradation of building materials and monuments due to the acidic nature of the pollutants (acid rain components).
Therefore,smog affects rubber,buildings,and monuments.

(D) Photochemical smog is formed by the action of sunlight on nitrogen oxides and hydrocarbons. The major components of photochemical smog include $PAN$ (Peroxyacetyl nitrate),$PBN$ (Peroxybenzoyl nitrate),and ozone $(O_3)$. Therefore,all the given options are major components of photochemical smog.

(A) The atmosphere is divided into several layers based on temperature and altitude.
The lowest layer of the atmosphere,which extends from the Earth's surface up to about $10$ to $15 \ km$,is known as the Troposphere.
This layer contains the air we breathe and is where most weather phenomena occur.

(A) The presence of excess nitrate in drinking water is harmful to human health,especially for infants. When nitrate levels exceed $45 \ ppm$,it leads to a condition known as 'blue baby syndrome' or $Methemoglobinemia$. In this condition,nitrate reduces the oxygen-carrying capacity of blood by converting hemoglobin to methemoglobin.

(B) Chlorine gas,when used in the bleaching process of paper pulp,reacts with the aromatic rings present in lignin to form toxic compounds known as dioxins. These are persistent organic pollutants.

(A) The term $Noosphere$ is derived from the Greek word $noos$ (mind) and $sphaira$ (sphere). It refers to the sphere of human thought or the biosphere transformed by human intelligence and activity to become an environment useful to humans.

(D) Statement $(1)$ is $True$ $(T)$: Plants obtain $C, H,$ and $O$ from $CO_2$ and $H_2O$.
Statement $(2)$ is $True$ $(T)$: Essential macronutrients like $N, P, K,$ and $Ca$ are absorbed by plants from the soil.
Statement $(3)$ is $False$ $(F)$: Compound fertilizers contain phosphorus as phosphates (e.g.,$Ca(H_2PO_4)_2$) and potassium as salts like $KCl$ or $K_2SO_4$,not as $PCl_3$ or $KO_2$.
Statement $(4)$ is $True$ $(T)$: $NPK$ fertilizers provide essential nutrients that significantly boost crop and vegetable yields.
Therefore,the correct sequence is $TTFT$. Since $TTFT$ is not explicitly listed,we evaluate the provided options. Given the standard curriculum context,the most accurate evaluation is $TTFT$. However,checking the provided options,if we assume statement $(3)$ is false,the sequence is $TTFT$. If the question implies a specific set,$TTFT$ is the scientific truth.

(A) The process of removal of the fertile top layer of soil by the action of natural agents like wind and water is known as $Soil \ erosion$. This leads to the loss of soil fertility and is a major environmental concern.

(C) Supersonic jet planes fly in the stratosphere. The exhaust gases from these planes contain nitrogen oxides,specifically $NO$ (nitric oxide). These nitrogen oxides react with ozone $(O_3)$ in the stratosphere,leading to the depletion of the ozone layer. The reaction is: $NO(g) + O_3(g) \rightarrow NO_2(g) + O_2(g)$.

(A) Atmospheric pollution is caused by substances that have harmful effects on the environment and living organisms.
$SO_2$ (Sulfur dioxide),$CO_2$ (Carbon dioxide),and $CO$ (Carbon monoxide) are known atmospheric pollutants.
$H_2$ (Hydrogen) is a clean fuel and does not cause atmospheric pollution upon combustion,as it produces only water $(H_2O)$ as a byproduct.

(A) The depletion of the ozone layer in the stratosphere is primarily caused by chlorofluorocarbons $(CFCs)$.
$CF_2Cl_2$ (dichlorodifluoromethane),commonly known as Freon-$12$,is a type of $CFC$.
In the stratosphere,these compounds break down under ultraviolet radiation to release chlorine radicals $(Cl^{\bullet})$,which catalyze the destruction of ozone $(O_3)$ into oxygen $(O_2)$.

(B) The term used for the heat-trapping ability of greenhouse gases is $GWP$,which stands for $Global \ Warming \ Potential$.
$GWP$ measures how much energy the emissions of $1 \ ton$ of a gas will absorb over a given period of time,relative to the emissions of $1 \ ton$ of carbon dioxide $(CO_2)$.

(C) The $Taj$ $Mahal$ is primarily threatened by acid rain,which is caused by the emission of $SO_2$ (sulfur dioxide) from industries like the $Mathura$ oil refinery.
$SO_2$ reacts with atmospheric moisture and oxygen to form sulfuric acid $(H_2SO_4)$,which corrodes the marble $(CaCO_3)$ of the monument.

(B) The $Biosphere$ is the global ecosystem composed of living organisms (biota) and the non-living (abiotic) factors from which they derive energy and nutrients. It encompasses all life on Earth and the physical environment with which it interacts.

(C) Classical smog is also known as London smog.
It occurs in cool and humid climates.
It is a mixture of smoke,fog,and sulfur dioxide $(SO_2)$.

(C) The atmosphere is divided into layers based on temperature. The troposphere is the lowest layer,extending up to $10-12 \ km$ from the Earth's surface. The stratosphere lies above it,extending up to $50 \ km$. Both $O_2$ and $N_2$ are major components of the atmosphere and are present in significant concentrations in both the troposphere and the stratosphere.

(B) Industrial waste is considered a major component of water pollution because it contains various toxic chemicals,heavy metals,and organic pollutants that are discharged directly into water bodies,significantly degrading water quality.

(B) The concept of the greenhouse effect was first proposed by $Joseph \ Fourier$ in $1824$. Later,$Svante \ Arrhenius$ and $Thomas \ Chamberlin$ provided a quantitative basis for how atmospheric carbon dioxide influences the Earth's surface temperature,establishing the analogy between the greenhouse effect and the Earth's atmosphere.

(A) Photosynthesis is a biological process where green plants,algae,and some bacteria convert light energy into chemical energy.
It is estimated that approximately $1800$ billion tons of oxygen are released into the atmosphere annually through this process,which is essential for the survival of aerobic organisms.

(C) $DDT$ (Dichlorodiphenyltrichloroethane) is a persistent organic pollutant. When sprayed on crops,it accumulates in the soil and can be washed away by rainwater into water bodies,leading to both soil and water pollution.

(D) Fluoride ions $(F^-)$ are essential for making teeth enamel much harder by converting hydroxyapatite,$[3Ca_3(PO_4)_2 \cdot Ca(OH)_2]$,into much harder fluorapatite,$[3Ca_3(PO_4)_2 \cdot CaF_2]$.
However,if the concentration of fluoride ions in drinking water exceeds $2 \ ppm$,it causes brown mottling of teeth.
At higher concentrations (above $10 \ ppm$),it causes harmful effects such as 'fluorosis',which leads to the stiffening of bones and mottling of teeth.

(B) Photochemical smog is formed by the reaction of nitrogen oxides $(NO_x)$ and volatile organic compounds $(VOCs)$ in the presence of sunlight.
$NO_2$ is a brown-colored gas that absorbs sunlight and undergoes photolysis to produce $NO$ and atomic oxygen $(O)$.
This $NO_2$ is responsible for the characteristic brownish haze observed in photochemical smog.

(D) Photosynthesis is a biological process in which green plants and other organisms convert light energy into chemical energy. During this process,plants absorb $CO_2$ from the atmosphere. It is estimated that approximately $2200$ crore tonnes of carbon dioxide are removed from the atmosphere annually through the process of photosynthesis.

(A) The global warming potential $(GWP)$ is a measure of how much heat a greenhouse gas traps in the atmosphere up to a specific time horizon,relative to carbon dioxide $(CO_2)$.
$CH_4$ (methane) has a $GWP$ of approximately $25$ to $28$ over a $100$-year period compared to $CO_2$.

(D) The relative contribution of various gases to global warming is as follows:
$CO_2: 50\%$
$CH_4: 19\%$
$CFC: 17\%$
$O_3: 8\%$
$N_2O: 4\%$
$H_2O: 2\%$
Therefore,$H_2O$ (water vapor) contributes the least to global warming among the given options.

(A) Acid rain is primarily caused by the emission of sulfur dioxide $(SO_2)$ and nitrogen oxides ($NO_x$,such as $NO_2$) into the atmosphere.
These gases react with water vapor in the atmosphere to form sulfuric acid $(H_2SO_4)$ and nitric acid $(HNO_3)$,which then fall to the ground as acid rain.
Therefore,the correct pair is $SO_2$ and $NO_2$.

(D) The greenhouse effect is primarily caused by greenhouse gases that trap heat in the atmosphere.
These gases include carbon dioxide $(CO_2)$,chlorofluorocarbons $(CFCs)$,methane $(CH_4)$,nitrous oxide $(N_2O)$,and water vapor.
Among the given options,$CO_2, CFC, CH_4$ and $NO_2$ are recognized greenhouse gases that contribute significantly to global warming.

(A) Acid rain is primarily caused by the emission of sulfur dioxide $(SO_2)$ and nitrogen oxides $(NO_x)$ into the atmosphere.
These gases react with water vapor and oxygen in the atmosphere to form sulfuric acid $(H_2SO_4)$ and nitric acid $(HNO_3)$,which then fall to the ground as acid rain.

(D) Carbon monoxide $(CO)$ is primarily produced by the incomplete combustion of fossil fuels and organic matter.
In industrial processes,the petrochemical industry and the paper and pulp industry are significant contributors to atmospheric $CO$ emissions due to the combustion processes involved in their operations.
Therefore,both $B$ and $C$ are major sources of $CO$ pollution.

(D) Water pollution can be controlled by various methods to remove contaminants.
$1$. Adsorption method: Uses adsorbents like activated carbon to remove organic pollutants.
$2$. Ion exchange method: Replaces undesirable ions with desirable ones,often used for water softening.
$3$. Reverse osmosis $(RO)$: Uses a semi-permeable membrane to remove ions,molecules,and larger particles from drinking water.
Since all these methods are effective for water purification and pollution control,the correct answer is $D$.

(A) Cadmium $(Cd)$ is a heavy metal that is highly toxic to humans and aquatic life. It is a well-known water pollutant that can enter water bodies through industrial waste,mining,and the use of fertilizers. Unlike $Na$ and $K$,which are essential minerals for biological processes,$Cd$ has no biological function and accumulates in the body,causing severe health issues like itai-itai disease.

(D) The ozone layer in the stratosphere acts as a shield by absorbing harmful ultraviolet $(UV)$ radiation from the sun.
Depletion of this layer allows more $UV$ radiation to reach the Earth's surface.
Increased exposure to $UV$ radiation is known to cause skin cancer in humans and animals,as well as damage to eyes and the immune system.

(D) Particulate pollutants are small solid particles or liquid droplets suspended in the air.
Examples include dust,mist,fumes,smoke,and $Fly \ ash$.
$Carbon \ dioxide$ $(CO_2)$,$Nitric \ oxide$ $(NO)$,and $Sulfur \ dioxide$ $(SO_2)$ are gaseous pollutants.
Therefore,$Fly \ ash$ is the correct answer.

(C) Carbon monoxide $(CO)$ binds to haemoglobin to form carboxyhaemoglobin,which is about $300$ times more stable than the oxygen-haemoglobin complex.
When the concentration of carboxyhaemoglobin reaches $3$ to $4\%$,it significantly reduces the oxygen-carrying capacity of blood,leading to headaches,weak eyesight,nervousness,and cardiovascular disorders.

(C) According to the standards set by the World Health Organization $(WHO)$ and environmental guidelines,the maximum permissible concentration of lead in drinking water is $50 \ ppb$ (parts per billion).

(B) The $CFC$ (Chlorofluorocarbons) and $BFC$ (Bromofluorocarbons) are major contributors to ozone depletion.
According to environmental chemistry data,there are approximately $95$ known derivatives of these compounds that are classified as $ODS$ (Ozone Depleting Substances).

(D) The troposphere is the lowest layer of the Earth's atmosphere. It contains various gaseous components such as $SO_x$,$NO_x$,and $CO_2$ due to natural and anthropogenic activities. Therefore,all the given options are present in the troposphere.