Pollution

"Pollution is the introduction of substances (or energy) that cause adverse changes in the environment and living entities .”

Pollution need not always be caused by chemical substances such as particulates (like smoke and dust). Forms of energy such as sound, heat or light can also cause pollution. These substances that cause pollution are called pollutants.

Types of Pollution

As stated before, there are different types of pollution, which are either caused by natural events (like forest fires) or by man-made activities (like cars, factories, nuclear wastes, etc.) These are further classified into the following types of pollution:

Air Pollution

Water Pollution

Noise Pollution

Soil Pollution

Besides these 4 types of pollution, other types exist such as light pollution, thermal pollution and radioactive pollution. The latter is much rarer than other types, but it is the deadliest.

Air Pollution

Air pollution refers to the release of harmful contaminants (chemicals, toxic gases, particulates, biological molecules, etc.) into the earth’s atmosphere. These contaminants are quite detrimental, and in some cases, pose serious health issues. Some causes that contribute to air pollution are:

• Burning fossil fuels
• Mining operations
• Exhaust gases from industries and factories

The effects of air pollution vary based on pollutant. But generally, the impact of air pollution range from:

• Increased risk of respiratory illness and cardiovascular problems
• Increased risk of skin diseases
• May increase the risk of cancer
• Global warming
• Acid rain
• Ozone depletion
• Hazards to wildlife

Water Pollution

Water pollution is said to occur when toxic pollutants and particulate matter are introduced into water bodies such as lakes, rivers and seas. These contaminants are generally introduced by human activities like improper sewage treatment and oil spills. However, even natural processes such as eutrophication can cause water pollution.

Other significant causes of water pollution include:

• Dumping solid wastes in water bodies
• Disposing untreated industrial sewage into water bodies
• Human and animal wastes
• Agricultural runoff containing pesticides and fertilisers

The effects of water pollution are very pronounced in our environment.  Furthermore, toxic chemicals can bioaccumulate in living beings, and these chemicals can travel their way up the food chain, ultimately reaching humans.

Among the other types of pollution, water pollution has a more disastrous consequences on humans. For instance, in 1932, a grave case of water pollution incapacitated the inhabitants of an entire city in Japan with neurological diseases and mental illness for many decades. However, the immediate cause not apparent but was eventually attributed to acute mercury poisoning. Methylmercury was dumped into the surrounding bay and had ultimately bioaccumulated inside the fish. The local population then consumed these fish, and this resulted in the manifestation of ill-effects and neurological diseases.

Other consequences of water pollution include:

• Disruption of the ecosystem
• Threats to marine life
• Increased risk of water-borne diseases
• Increases toxic chemicals (such as mercury) in water bodies
• Eutrophication

Soil Pollution

Soil pollution, also called soil contamination, refers to the degradation of land due to the presence of chemicals or other man-made substances in the soil. The xenobiotic substances alter the natural composition of soil and affect it negatively. These can drastically impact life directly or indirectly. For instance, any toxic chemicals present in the soil will get absorbed by the plants. Since plants are producers in an environment, it gets passed up through the food chain. Compared to the other types of pollution, the effects of soil pollution are a little more obscured, but their implications are very noticeable.

Some of the common causes of soil pollution are:

• Improper industrial waste disposal
• Oil Spills
• Acid rain which is caused by air pollution
• Mining activities
• Intensive farming and agrochemicals (like fertilisers and pesticides)
• Industrial accidents

The effects of soil pollution are numerous. Specific wastes, such as radioactive waste become particularly hazardous when they are not well-contained. A well-documented example is a nuclear accident in Chernobyl, which has left an area of 2,600 km² uninhabitable for several thousand years.

Other effects of soil pollution include:

• Loss of soil nutrients, which renders the soil unfit for agriculture
• Impacts the natural flora and fauna residing in the soil
• Degrades vegetation due to the increase of salinity of the soil
• Toxic dust (such as silica dust) can cause respiratory problems or even lung cance

Noise Pollution

Noise pollution refers to the excessive amount of noise in the surrounding that disrupts the natural balance. Usually, it is man-made, though certain natural calamities like volcanoes can contribute to noise pollution.

In general, any sound which is over 85 decibels is considered to be detrimental. Also, the duration an individual is exposed plays an impact on their health. For perspective, a normal conversation is around 60 decibels, and a jet taking off is around 15o decibels. Consequently, noise pollution is more obvious than the other types of pollution.

Noise pollution has several contributors, which include:

• Industry-oriented noises such as heavy machines, mills, factories, etc.
• Transportation noises from vehicles, aeroplanes, etc.
• Construction noises
• Noise from social events (loudspeakers, firecrackers, etc.)
• Household noises (such as mixers, TV, washing machines, etc.)

Noise pollution has now become very common due to dense urbanisation and industrialisation. Noise pollution can bring about adverse effects such as :

• Hearing loss
• Tinnitus
• Sleeping disorders
• Hypertension (high BP)
• Communication problems

Questions:

1. Define the term"Pollution".

2. What are the effects of soil pollution?

3. What are the consequences of water pollution?

PROJECT - +2

Scientific investigations involving laboratory testing and collecting information from other sources.

A few suggested Projects.

�� Study of the presence of oxalate ions in guava fruit at different stages of ripening.

�� Study of quantity of casein present in different samples of milk.

�� Preparation of soybean milk and its comparison with the natural milk with respect to curd

formation, effect of temperature, etc.

�� Study of the effect of potassium bisulphate as food preservative under various conditions

(temperature, concentration, time etc.)

�� Study of digestion of starch by salivary amylase and effect of pH and temperature on it.

�� Comparative study of the rate of fermentation of following materials: wheat flour, gram

flour, potato juice, carrot juice etc.

�� Extraction of essential oils present in Saunf (aniseed), Ajwain (carum), Illaichi (cardamom).

�� Study of common food adulterants in fat, oil, butter, sugar, turmeric powder, chilli powder

and pepper.

Note: Any investigatory project,

PRACTICALS SYLLABUS- Plus 2

A. Surface Chemistry (Periods 6)
(a) Preparation of one lyophilic and one lyophobic sol
Lyophilic sol - starch, egg albumin and gum
Lyophobic sol - aluminium hydroxide, ferric hydroxide, arsenous sulphide.
(b) Study of the role of emulsifying agents in stabilizing the emulsions of
different oils.
B. Chemical Kinetics (Periods 4)
(a) Effect of concentration and temperature on the rate of reaction between sodium
thiosulphate and hydrochloric acid.
(b) Study of reaction rates of any one of the following:
(i) Reaction of iodide ion with hydrogen peroxide at room temperature
using different concentration of iodide ions.
(ii) Reaction between potassium iodate, (KIO3) and sodium sulphite: (Na2SO3)
using starch solution as indicator (clock reaction).
C. Thermochemistry (Periods 4)
Any one of the following experiments
i) Enthalpy of dissolution of copper sulphate or potassium nitrate.
ii) Enthalpy of neutralization of strong acid (HC1) and strong base (NaOH)
iii) Determination of enthalpy change during interaction (hydrogen bond formation)
between acetone and chloroform
D. Electrochemistry (Period 2)
Variation of cell potential in Zn/Zn2+||Cu2+/Cu with change in concentration of
electrolytes (CuSO4 or ZnSO4) at room temperature.
91
E. Chromatography (Periods 2)
i) Separation of pigments from extracts of leaves and flowers by paper chromatography
and determination of Rf values.
ii) Separation of constituents present in an inorganic mixture containing two cations
only (constituents having large difference in Rf values to be provided).
F. Preparation of Inorganic Compounds (Periods 4)
i) Preparation of double salt of ferrous ammonium sulphate or potash alum.
ii) Preparation of potassium ferric oxalate.
G. Preparation of Organic Compounds (Periods 4)
Preparation of any two of the following compounds
i) Acetanilide
ii) Di-benzal acetone
iii) p-Nitroacetanilide.
iv) Aniline yellow or 2 - Naphthol aniline dye.
v) Iodoform
H. Tests for the functional groups present in organic compounds: (Periods 6)
Unsaturation, alcoholic, phenolic, aldehydic, keton, carboxylic and amino (primary) groups.
I. Characteristic tests of carbohydrates, fats and proteins in pure samples and
their detection in given food stuffs. (Periods 4)
J. Determination of concentration/molarity of KMnO4 solution
by titrating it against a standard solution of: (Periods 8)
i) Oxalic acid,
ii) Ferrous ammonium sulphate
(Students will be required to prepare standard solutions by weighing themselves).
K. Qualitative analysis (Periods 14)
􀁺Determination of one cation and one anion in a given salt.
Cations - Pb2+, Cu2+, As3+, Al3+, Fe3+, Mn2+, Zn2+, Co2+, Ni2+, Ca2+, Sr2+, Ba2+, Mg2+,
NH4
+
Anions - CO3
2-, S2-, SO3
2-, SO4
2-, NO2
–, NO3
–, Cl –, Br–, I–, PO4
3-; C2O4
2-, CH3COO–
(Note: Insoluble salts excluded)

CBSE Syllabus of Plus 2

Unit I: Solid State (Periods 12)

Classification of solids based on different binding forces: molecular, ionic, covalent and metallic

solids, amorphous and crystalline solids (elementary idea), Crystal Lattices and unit cells,

calculation of density of unit cell, packing in solids, voids, number of atoms per unit cell in a cubic

unit cell, point defects, electrical and magnetic properties.

Unit II: Solutions (Periods 12)

Types of solutions, expression of concentration of solutions of solids in liquids, solubility of gases

in liquids, solid solutions, colligative properties – relative lowering of vapour pressure, elevation

of boiling point, depression of freezing point, osmotic pressure, determination of molecular masses

using colligative properties, abnormal molecular mass.

Unit III: Electrochemistry (Periods 14)
Redox reactions, conductance in electrolytic solutions, specific and molar conductivity, variations
of conductivity with concentration, Kohlrausch’s Law, electrolysis and laws of electrolysis
(elementary idea), dry cell – electrolytic cells and Galvanic cells, lead accumulator, EMF of a
cell, standard electrode potential, Nernst equation and its application to chemical cells, fuel cells,
corrosion.
Unit IV: Chemical Kinetics (Periods 12)
Rate of a reaction (average and instantaneous), factors affecting rate of reaction: concentration,
temperature, catalyst order and molecularity of a reaction, rate law and specific rate constant,
integrated rate equations and half life (only for zero and first order reactions), collision theory
(elementary idea, no mathematical treatment)
Unit V: Surface Chemistry (Periods 8)
Adsorption – physisorption and chemisorption, factors affecting adsorption of gases on solids,
catalysis : homogenous and heterogeneous, activity and selectivity, enzyme catalysis; colloids
distinction between true solutions, colloids and suspensions; lyophilic, lyophobic, multimolecular
and macromolecular colloids; properties of colloids; Tyndall effect, Brownian movement,
electrophoresis, coagulation, emulsion – types of emulsions.
Unit VI: General Principles and Processes of Isolation of Elements
(Periods 8)
Principles and methods of extraction - concentration, oxidation, reduction-electrolytic method
and refining; occurrence and principles of extraction of aluminium, copper, zinc and iron.
Unit VII: p-Block Elements (Periods 14)
Group 15 Elements: General introduction, electronic configuration, occurrence, oxidation states,
trends in physical and chemical properties; nitrogen - preparation, properties and uses; compounds
of nitrogen: preparation and properties of ammonia and nitric acid, oxides of nitrogen (structure
only); Phosphorous-allotropic forms, compounds .of phosphorous: preparation and properties
of phosphine, halides (PCl3, PCl5) and oxoacids (elementary idea only)
Group 16 Elements: General introduction, electronic configuration, oxidation states, occurrence,
trends in physical and chemical properties; dioxygen: preparation, properties and uses, simple
oxides, Ozone, Sulphur - allotropic forms; compounds of sulphur: preparation, properties and
uses of sulphur dioxide, sulphuric acid: industrial process of manufacture, properties and uses,
oxoacids of sulphur (structures only).
88
Group 17 elements: General introduction, electronic configuration, oxidation states, occurrence,
trends in physical and chemical properties; compounds of halogens, preparation, properties and
uses of chlorine and hydrochloric acid, interhalogen compounds, oxoacids of halogens
(structures only).
Group 18 elements: General introduction, electronic configuration, occurrence, trends in physical
and chemical properties, uses.
Unit VIII: d and f Block Elements (Period 14)
General introduction ,electronic configuration, occurrence and characteristics of transition metals,
general trends in properties of the first row transition metals – metallic character, ionization enthalpy,
oxidation states, ionic radii, colour, catalytic property, magnetic properties, interstitial compounds,
alloy formation, preparation and properties of K2Cr2O7 and KMnO4.
Lanthanoids - electronic configuration, oxidation states, chemical reactivity and lanthanoid
contraction.
Actinoids - Electronic configuration, oxidation states.
Unit IX: Coordination Compounds (Period 12)
Coordination compounds - Introduction, ligands, coordination number, colour, magnetic
properties and shapes, IUPAC nomenclature of mononuclear coordination compounds. bonding,
isomerism, importance of coordination compounds (in qualitative analysis, extraction of metals
and biological systems).
Unit X: Haloalkanes and Haloarenes. (Periods 12)
Haloalkanes: Nomenclature, nature of C-X bond, physical and chemical properties, mechanism
of substitution reactions.
Haloarenes: Nature of C-X bond, substitution reactions (directive influence of halogen in
monosubstituted compounds only)
Uses and environmental effects of - dichloromethane, trichloromethane, tetrachloromethane,
iodoform, freons, DDT.
Unit XI: Alcohols, Phenols and Ethers (Periods 12)
Alcohols: Nomenclature, methods of preparation, physical and chemical properties (of primary
alcohols only), identification of primary, secondary and tertiary alcohols, mechanism of dehydration,
uses of methanol and ethanol.
Phenols : Nomenclature, methods of preparation, physical and chemical properties, acidic
nature of phenol, electrophillic substitution reactions, uses of phenols.
Ethers: Nomenclature, methods of preparation, physical and chemical properties, uses.

Unit XII: Aldehydes, Ketones and Carboxylic Acids (Periods 12)
Aldehydes and Ketones: Nomenclature, nature of carbonyl group, methods of preparation,
physical and chemical properties, mechanism of nucleophilic addition, reactivity of alpha
hydrogen in aldehydes; uses.
Carboxylic Acids: Nomenclature, acidic nature, methods of preparation, physical and chemical
properties; uses.
Unit XIII: Organic compounds containing Nitrogen (Periods 10)
Amines: Nomenclature, classification, structure, methods of preparation, physical and chemical
properties, uses, identification of primary, secondary and tertiary amines.
Cyanides and Isocyanides - will be mentioned at relevant places in context.
Diazonium salts: Preparation, chemical reactions and importance in synthetic organic chemistry.
Unit XIV: Biomolecules (Periods 12)
Carbohydrates - Classification (aldoses and ketoses), monosaccahrides (glucose and fructose),
oligosaccharides (sucrose, lactose, maltose), polysaccharides (starch, cellulose, glycogen),
importance.
Proteins - Elementary idea of α - amino acids, peptide bond, polypeptides, proteins, structure
of proteins-primary, secondary, tertiary structure and quaternary structures (qualitative idea only),
denaturation of proteins, enzymes.
Vitamins -Classification and functions.
Nucleic Acids: DNA and RNA .
Unit XV: Polymers (Periods 8)
Classification - natural and synthetic, methods of polymerization (addition and condensation),
copolymerization, some important polymers: natural and synthetic like polythene, nylon,
polyesters, bakelite, rubber.
Unit XVI: Chemistry in Everyday life (Period 8)
Chemicals in medicines - analgesics, tranquilizers, antiseptics, disinfectants, antimicrobials,
antifertility drugs, antibiotics, antacids, antihistamines.
Chemicals in food - preservatives, artificial sweetening agents.
Cleansing agents - soaps and detergents, cleansing action.

Mark weightage for Plus 2

One Paper Time: 3 Hours 70 marks
Unit No. Title Marks
Unit I Solid State 4
Unit II Solutions 5
Unit III Electrochemistry 5
Unit IV Chemical Kinetics 5
Unit V Surface Chemistry 4
Unit VI General Principles and Processes of Isolation of Elements 3
Unit VII p-Block Elements 8
Unit VIII d- and f- Block Elements 5
Unit IX Coordination Compounds 3
Unit X Haloalkanes and Haloarenes 4
Unit XI Alcohols, Phenols and Ethers 4
Unit XII Aldehydes, Ketones and Carboxylic Acids 6
Unit XIII Organic Compounds containing Nitrogen 4
Unit XIV Biomolecules 4
Unit XV Polymers 3
Unit XVI Chemistry in Everyday Life 3
Total: 70