Chemistry in everyday life - Class XII notes

1. CHEMISTRY IN EVERYDAY LIFE – NOTES
CHEMOTHERPY: - chemical substances of natural or synthetic origin which are used for curing
diseases and reducing suffering from pain are called Medicines. The branch of science which deals
with the treatment of diseases using chemicals is called Chemotherapy.
Classification of Medicines

• Analgesics:-These are the Medicines used for getting relief from pain. they are further
classified into
• Narcotics: which produce sleep and unconsciousness such as Morphine, (these are
Habit forming) they are effective analgesics, another narcotic is Marijuana which is
also used as Analgesic.
• Non -Narcotics:- aspirin(2-Acetoxybenzoic acid) commonly used as analgesic with
antipyretic (Temperature lowering)properties, it has anti blood clotting action also,
so it is used to prevent heart attack these days. it is liver toxic in nature
• Tranquilizers or Hypnotics :-these drugs act on the central nervous system(CNS) and help in
reducing stress and fatigue by inducing sense of well being . They are also called
psychotherapeutic drugs. these drugs are helpful in reducing depression and emotional
stress such as
• Barbituaric Acid,Luminal, Chlorodiazapoxide,Equanil, Valium(Diazepam), Serotonin.
• Antiseptics:- these are chemical substances which prevent the growth of Micro-organisms
and may even kill them. they are applied on wounds,cuts or ulcers in the form of powder or
cream such as soframycin, furacins etc.
• Disinfectant:- these are chemical substances which kill micro-organisms, but are not
safe to apply on living tissues
• The same substance can act as antiseptic or disinfectants also depending upon the
concentration of the solution used. EXAMPLE:- 0.2% solution of phenol is antiseptic
whereas 1% solution is disinfectant.
• EXAMPLES OF DISINFECTANTS:-
• DETTOL- it is an antiseptic and mixture of chloroxylenol and Terpineol
• Savlon
• Bithionol
• Iodine
• Boric Acid
• Cresols or Lysols
• H202

• ANTIMICROBIALS:- these are divided into i) Antibiotics ii) Supha drugs. Drugswhich are used
such as used to cure diseases caused by Microbes Bacterias,Virus,Fungi, these include
antibacterials,antifungals and antiviral agents.
• All micro-organism which cause disease are called Pathogens. These pathogens
enter the body and multiply inside Host cell and destroy the host cell metabolism.
they produce toxins(poisonous substances) and cause the diseases.
• The diseases caused by them can be controlled by giving drugs such as
• Bactericidal Drugs- (Drug which kill the Microbes in the body.)
• Such as :- Penicillin,Aminoglycosides(Streptomycin),Ofloxacin,
• Bectrioststic Drugs:- Erythromycin, Tetracyclin, Chloramphenicol , Cephalosporins..
• The full range of microrganisms attcked by an antibiotic is called Spectrum Broad spectrum
Antibiotics are effective against sevral different types of bacteria.

2. • Tetracyclin, Vanomycin, Ofloxacin are highly is Broad spectrum antibiotics.
• Chloramphenicol is another Broad Spectrum Antibiotic which is repidly absorbed
from the Gastro-instestinal track hence can be orally given in the treament of
typhoid, dysentry, acute fever, UTI's, Meningitis,and Pneumonia etc..
• Streptomycin can be given for Tuberclosis (Specific Use)
• Penicillin has a narrow spectrum therefore given for diseases caused by Cocci and
gram Positive Bacteria. therefore test has to be conducted before given such
antibiotic(Ampicillin and Amoxycillin)
• Sulpha Drugs:- A group of drugs which are the derivatives of Sulphanilamides . these have
great antibacterial powers and used in the treament of Diptheria,tuberclosis caused by
streptococci,gonococci and pneumo-cocci infections.
• Examples of Sulpha Drugs and Uses
• Sulphanilamide:- Used for UTI, RTI,
• Sulphadiazine:- Used for Dysentry,this drug is less toxic
• Sulphaguandine:- Used for severe Bacillary Dysentry
• Sulphapyridine:- Used for Pneumonia......................
• Antifertility Drugs:- Chemical substances which are used to check the pregenancy in
women or they are used as Birth Control Drugs. They are also called Oral
Contraceptives. they are used to regulate Menstrual cycles and ovulations.
Example:- Enovid-E.
• Antihistamins:- these are called Anti-allergic drugs . they are used to treat skin
rashes, inflamation of tissues, asthama and itching of hives.
• Further they also used in the treatment of fever,Conjuctivities, Rhinitis, Sneezing,
Nasal discharge, itching of nose ,throat, nausea .
• Examples:- Diphenylhydramine, cetrizine, Avil, Chlorophenramine, Promethazine ,
cimidine , ranitidine(Zantac), Histamin. Histamin is a potent vasodilator , it contrcts
the smooth muscles in bronchi and gut and relaxes other muscles. Brompheniramine
and Terfenadine act as Histamins.

Antacids:- Substances which neutralizes the excess acid and raise the Ph to an appropriate level in
stomach.
During Acid Gastritis, the acid produced (HCI) in the gastric juices , the commonly used antacids are
weak bases Mg(0H)2, MgC03, AI(oH)3, hydroxide gel, NaHC03, AI(P04)3. These days Omeprazole and
Lansoprazole are being used widely.

• CLASSIFICATION OF DRUGS:-
• A) On the basis of Pharmacologicla effects
• B) On the basis of drug Action
• C) On the basis of Chemical structure
• D) On the basis of Molecular Targets
• B:- On the basis of drug action , drug is given based on particular Bio-chemical
process.
• A. On the basis of pharmacological effects, it is easier for the doctors to prescribe and
choose from the wide range of drugs for the patient depending upon the type of disease

3. • C. On the basis of structural similarities, drugs are often given because they have
common features in them and similar pharmcological activities.
• D. Normally all the drugs interact with biomolecules such as carbohydrates, lipids and
proteins as well as Nucleic acids these are called target molecules or drug-Targets . hence
these drugs can be given based on Drug Targets.
• Catalytic Action Of Enzymes:- The first function of enzymes is to hold the substrate for a
chemical reaction.Active sites hold the substrate molecule in a perticular position, so that
attack of the reagent should be effective, then substrate binds the active site of the enzyme
through ionic or Hydrogen Bonding or Vander-Waal forces and may be Dipole-Dipole
interactions. The second function of the enzymes is to provide the functional group which
will attack the substrate and carry out chemical reaction. Drugs which stops the substrate
from attaching at the site of enzyme are called Competitive Inhibitors . Whereas the drugs
which do not bind to the active site are called Allosteric site. They change the shape of active
site so that substrate can not recognize it. if the bond between the and the inhibitors is
strong covalent then enzyme is permanently blocked, then the synthesis of new enzyme
takes place.
• Receptors as drug Targets:- Receptors are proteins that are crucial to body's communication
process, they are embedded in cell membranes and posesses active sites out of the surface
of the membrane. In our body, message between two neurons and between neurons and
muscles is communicated through certain chemicals called chemical Messengers. Chemical
messengers are recieved at the binding sites of receptors proteins. To accomodate a
messenger shape of the site changes. There are large numbers of receptors present in the
body which interact with different chemical messengers. these are selective in nature.

• CHEMICALS IN FOOD :- Chemicals are added to food for(i) their preservation (ii) Enhancing
their appeal (iii) Adding nutritive value in them. These are called Food Additives.
• FOOD ADDITIVES:- 1. FOOD COLOURS 2. FLAVOURS AND SWEETNERS 3. FAT
EMULSIFIERS AND STABLISING AGENTS 4. FLOUR IMPROVERS-ANTISTALINF AGENTS
AND BLEACHES 5. ANTIOXIDENTS. 6. PRESERVATIVES.7. NUTRITIONAL SUPPLIMENTS
-MINERALS,VITAMINS, AND AMINO ACIDS
• ARTIFICIAL SWEETENING AGENTS:- Natural sweeteners such as Sucrose, add to calorie
intake. Ortho-Sulphobenzemide is called SACCHARINE. It is about 500 times sweet as cane
sugar. it is excreated from the urine unchanged. its good for the Diabetic persons. EXAMPLES
OF ARTIFICIAL SWEETNERS:- ASPARTAME, SACCHARIN, SUCROLOSE, ALITAME. Aspartame is
the most successful and widely used sweetner.it is methyl ester of dipeptide formed from
aspartic acid and phenylalanine. it is used in soft-drinks and cold foods because it is unstable
at cooking temperature. Alitame is more stable than aspartame whereas sucrolose is tri-
choloro-Derivative of sucrose.
• FOOD PRESERVATIVES:- Food preservatives are used to preserve the food due to Microbial
Growth. They are:- Table salt, vegetable oils, Sugar, Sodium Benzoate, Sodium Benzoate is

4. used in limited quantities because it is Metabolized in the body. Salts of Sorbic Acid and
Propanoic Acid are also used as preservatives.
• Cleansing Agents
• The word detergent means cleansing agent. Actually detergent word is derived from Latin
word „detergere‟ means “to wipe off”, Cleansing agents are the substance which remove
dirt and have cleansing action in water. These are also called surfactants.
• Detergents can be classified into two types.
• 1. Soapy detergents or soaps, and
• 2. Non-soapy detergents or soap less soap.
• 1. Soaps
• Soaps are sodium or potassium salts of higher fatty acids (containing 15-18 carbon atoms)
e.g., stearic acid, oleic acid and palmitic acid. Sodium salts of fatty acids are known as hard
soaps while the potassium salts of fatty acids are known as soft soaps.
• Hard soaps are prepared by cheaper oil and NaOH while soft soaps are prepared by oil of
good quality and KOH. The soft soaps do not contain free alkali, produce more lather and are
used as toilet soaps, shaving Soaps and shampoos.
• Preparation of soaps
• Soaps containing „Sodium salts are formed by heating fat (glyceryl ester ~fatty acid) with
aqueous sodium hydroxide solution. This reaction is known as saponification.
•
•
•
• The solution left after removing the soap contains glycerol, which can be recovered by
fractional distillation. To improve the quality of soaps desired colours, perfumes and
medicinal chemical substances, added.
• Types of Soaps
• Different kind of soaps are made by using different raw materials.
• 1. Toilet soaps These are prepared by using better grade of fat or oil and care is taken to
remove excess alkali. Colour and perfumes are added to make these more attractive.
• 2. Floating soaps These can be prepared by beating tiny bubbles into the product before it
hardens.
• 3. Transparent soaps These are made by dissolving the in ethanol and then evaporating the
excess solvent.
• 4. Medicated soaps Medicated soaps are prepared by some antiseptics like dettol or
bithional.
• 5. Shaving soaps These contain glycerol to prevent drying. A gum called rosin is added while
making them. It forms sodium rosinate which lather well.

5. • 6. Laundry soaps These sodium silicate, borax and contain sodium fillers like carbonate.
sodium rosins
• 7. Soap Chips These are made by running a thin sheet of melted soap on a cool cylinder and
scraping off the soaps in small broken pieces.
• 8. Soap granules These are dried miniature soap bubbles.
• 9. Soap powder and scouring soaps these contain a scouring agent (abrasive) such as
powdered pumice or finely divided sand and builders like sodium carbonate and trisodium
phosphate. Builders make the soaps act more quickly.
• Disadvantages of Soaps
• Soap is good cleansing agent and is 100% biodegradable microorganisms present in sewage
water can completely oxidise soap to CO2, As a result, it does not create any pollution
problem.
• However soaps have two disadvantages:
• (i) Soaps cannot be used in hard water since calcium magnesium ions present in hard water
produce curdy precipitates of calcium and magnesium soaps.
•
•
• These insoluble soaps separate as scum in water and causes hindrance to washing because
the precipitate adheres onto the fibre of the cloth as gummy mass. Thus, a lot of soap is
wasted if water is hard.
• (ii) Soaps cannot be used in acidic solutions since acids precipitate the insoluble free fatty
acids which adhere to the fabrics and thus, reduce the ability of soaps to remove oil and
grease from fabrics.
•
• Soapless Soap/Synthetic Detergents
• Synthetic detergents have all the properties of soaps but actually do not contain any soap,
so they are known as „soapless soaps‟.
• Straight chain alkyl group containing detergents are biodegradable whereas branched chain
alkyl group containing detergents are non-biodegradable.
• Unlike soaps, synthetic detergents can be used in both soft and hard water. This is due to
the reason that calcium and magnesium salts of detergents like their sodium salts are also
soluble in water. Synthetic detergents are mainly classified into three categories:
• 1. Anionic Detergents
• These are sodium salts of sulphonated long chain alcohols or hydrocarbons.
• (i) Alkyl hydrogen sulphates formed by treating long chain alcohols with concentrated
sulphuric acids are neutralised with alkali to form anionic detergents.

6. •
• (ii) Alkyl benzene sulphonates are obtained by neutralising alkyl benzene sulphonic acids
with alkali.
•
• In such detergents, the anionic part of the molecule is involved in the cleansing action. They
are mostly used for household work and in tooth paste
• 2. Cationic Detergents
• These are quaternary ammonium salts containing one or more long chain alkyl group with
acetates, chlorides or bromides as anion. For example,
• Cationic detergents are used in hair conditioner. They have germicidal properties but are
expensive therefore, these are of limited use.
• 3. Non-ionic Detergents
• Such detergents do not contain any ion in their constitution. One such detergent can be
obtained by reaction of stearic acid and polyethylene glycol.
•
• Liquid dish washing detergents are non-ionic type; Mechanism of cleansing action of this
type of detergents is the same as that of soaps.
• Advantages of synthetic detergents over soaps

7. • 1. Synthetic detergents can be used even in case of hard water whereas soaps fail to do so.
• 2. Synthetic detergents can be used in the acidic medium while soaps cannot because of
their hydrolysis to free acids.
• 3. Synthetic detergents are more soluble in water and hence, form better lather than soaps.
• 4. Synthetic detergents have a stronger cleansing action than soaps.