Page 1 :
chemistry notes by azeem Sir, , joint my Telegram channel-https://t.me/stateboard11, , class 11 maharashtra notes, , 16. Chemistry in Every Day Life, , Si, r, , 1. The life, the atmosphere, the earth and the universe, all have evolved over billions of years to the present, state., 2. The evolution continues progress and accompanied by a variety of chemical changes., 3. Natural phenomena such as weathering, lightening, irruption of volcanoes, photosynthesis, ripening of fruit,, fermentation, release of fragrance by blooming flowers and many others take around us involve intricate chemistry., 4. Chemistry is involved in a variety of life processes those occur within and across our body., 5. Human civilization in different regions of the world discovered uses of various plant, animal and mineral, products for benefits of human life., 6. With the advent of modern science, scientist discovered structures of various constituent chemicals in natural, materials., 7. Synthetic organic chemistry has led to advancement in science., 8. Synthesis of natural molecules and new molecules with structural variation revolutionized materials are used in, all the walks of human life., 9. This influence is seen in all aspects of the basic needs, such as food, clothing, shelter and beyond., 10. In this chapter, we consider some aspects of food chemistry, medicinal chemistry and chemistry of cleansing, materials with reference to compounds having simple structural features., , Az, , ee, m, , 16.1 Basics of food chemistry, 1. Food provides nutrients these are used by the body as the source of energy., 2. These nutrients also regulate growth, maintain and repair body tissues., 3. The nutrients comprise carbohydrates, lipids, proteins. vitamins, minerals and water., 4. Grains, fruits and vegetables provide carbohydrates and vitamins; meat, fish, eggs, dairy products and pulses, provide proteins and vitamins., 5. Lipids are provided by vegetable oils, dairy products and animal fats., 6. Most nutrients are organic macromolecules., 7. Proteins and carbohydrates are polymeric materials., 8. As a result of food digestion, the polymeric proteins and carbohydrates ultimately break down into monomers,, namely, πΌ - amino acids and glucose, respectively, under the influence of enzymes., 9. Cooking makes food easy to digest., 10. During the cooking process, high polymers of carbohydrates or proteins are hydrolysed to smaller polymers., 11. The uncooked food mixture, described as heterogeneous suspension, becomes a colloidal matter on cooking., 12. Because of smaller size of the resulting constituent nutrient molecules, cooked food is easier to digest than, the uncooked food., 16.1.2 Food quality chemistry :, 1. Quality of food is an important aspect of food chemistry., 2. Food quality is described in terms of parameters such as flavour, smell, texture, colour and microbial spoilage., Enzymes are present naturally in all foods., 3. Quality of foods changes on shelving mostly due to enzyme action, chemical reactions with the environment and, the action of microorganisms., 4. Some of these effects are beneficial., 5. For example, setting of milk into curd and raising flour dough to make bread is brought about by deliberate, action of microorganisms., 6. Most changes brought about by microorganisms and interaction with the environment however, adversely affect, the food quality., 7. Food preservation and food processing methods aim at prevention of undesirable changes and attempt about, desirable changes in food.
Page 2 :
chemistry notes by azeem Sir, , joint my Telegram channel-https://t.me/stateboard11, , class 11 maharashtra notes, , The following cases illustrate some aspects of food quality, and the underlying chemistry., i. Browning of cut fruit/vegetables :, 1. When fruits such as banana, apple or vegetables such as, potato, bottelgourd are peeled and sliced, sooner or later, they turn brown., 2. Cutting action damage the cells resulting in release of, chemicals., 3. With the pH prevailing in fruit/ vegetables, the polyphenols released are oxidised with oxygen in air owing to, action from an enzyme to form quinones., 4. Quinones undergo further reactions including polymerization giving brown coloured products named tannins., 5. This browning reaction can be slowed down using reducing agents such as SO2 , ascorbic acid (vitamin C) or by, change of pH by adding edible acid such as lemon juice (citric acid) or vinegar., , ee, m, , Si, r, , ii. Rancidity of oils and fats :, 1. On keeping for long time, oils and fats develop an unpleasant or rancid smell and disagreeable taste., 2. Fats are triesters of fatty acids (long chain carboxylic acids) and glycerol (propane - 1, 2, 3 - triol)., 3. One cause of rancidity is release of fatty acids produced during hydrolysis of fats brought about by water, present in food., , Az, , 4. The hydrolysis of fats occurs rapidly in the presence of certain microorganisms and is an enzyme catalysed, reaction., 5. Rancidity of milk and butter is due to the release of four, six and eight carbon fatty acids (butanoic, hexanoic, and octanoic acids) on hydrolysis., 6. Chocolate develops oily or fatty flavour due to release of palmitic, stearic and oleic acids on hydrolysis., 7. Lauric acid on hydrolysis gives a soapy flavour to coconut oil., 8. The second cause of rancidity of oils and fats is oxidation by molecular oxygen in the air., 9. Many vegetable oils have one or more C = C double bonds in the fatty acid part of their structure., 10. These are called mono or poly unsaturated fats., 11. The unsaturated fat molecules break down during the oxidation and form volatile aldehydes and carboxylic, acids which give the unpleasant rancid taste. This is called oxidative rancidity., 12. It is caused by free radical reaction initiated by light (photo oxidation) or catalysed by either enzymes or, metal ions., 13. Polyunsaturated oils containing greater number of C = C double bonds and usually become rancid very quickly., 14. High temperature increases the rate of air oxidation of unsaturated fats., 15. Extensive oxidation can leads to some polymerization with consequent increase in viscosity and browning., iii. Saturated, unsaturated and trans fats :, 1. You have noted earlier that fats are triglycerides of fatty acids., 2. Animal fats mostly contain saturated fatty acids, while vegetable oils contain unsaturated fatty acids as well., 3. Long chains of tetrahedral carbon atoms in a saturated fatty acid get packed closely together., 4. Moreover, van der Waal's forces between the long saturated chains are sufficiently strong to convert saturated, fats into solid form at room temperature., 5. The long carbon chains of unsaturated fatty acids contain one or more C = C double bonds.
Page 3 :
chemistry notes by azeem Sir, , joint my Telegram channel-https://t.me/stateboard11, , class 11 maharashtra notes, , ee, m, , Si, r, , 6. This produces one or more 'kinks' in the chain, (see the Fig. 16.1) which prevent the molecules from packing, closely together., 7. The van der Woals forces between the unsaturated chains are weak., 8. The melting points of unsaturated fats therefore, are lower., 9. Natural fats are mixtures of triglycerides., 10. They do not have sharp melting points, and usually melt over a range of temperatures., 11. The more unsaturated the fat lower is its melting point and less crystalline it is., 12. Some examples of fats are given in Table ππ. π., 13. AC = C can have geometrical isomers cis and trans., 14. In the cis form of an unsaturated fatty acid the two hydrogens on the two double bonded carbons are on the, same side of the double bond, whereas they are on the opposite sides in the trans isomer., 15. The cis isomer is the most common form of unsaturated fats., 16. The trans form occurs only in animal fats and processed unsaturated fats., 17. Trans fats are difficult to metabolize and may build up to dangerous levels in fatty tissue., 18. Fats in the form of lipoprotein are used in the body for transport of cholesterol., 19. Excessive low density lipoprotein (I.DL) results in deposition of cholesterol in blood vessels, which in tum,, results in the increased risk of cardio vascular disease., 20. There is some evidence that eating large amounts of saturated of trans unsaturated fats, increase the, tendency of cholesterol getting deposited in blood vessels., 21. Cis fats do not cause formation of such deposits and decrease chance of developing coronary heart disease., , Table 16.1: Natural fats and their physical states, Mainly monounsaturated fats, , Mainly poly-unsaturated fats, , Coconut fat/oil, butter fat, lard,, margarine, vanaspati ghee, , Olive oil, peanut oil,, canola oil, , Safflower oil, sunflower oil, soyabean, oil, corn oil, fish oil, , solid, , liquid, , liquid, , Az, , Mainly Saturated fats, , iv. Omega-3 :, 1. Two categories of the natural unsaturated fats of concern include those containing either Omega-3 or Omega6 fatty acids., 2. These names are given for the position of the double bond in a long carbon chain of the fatty acid., 3. Omega denotes the last carbon of the carbon chain., 4. Omega- 3 fatty acids have C = C bond between the third and fourth carbon from the end of a carbon chain., 5. For example: Linolenic Acid (9,12,15-octadecatrienoic acid), 6. Omega- 3 fats are found to raise the High density lipoprotein HDL (good cholesterol) level of blood., 7. On the contrary, Omega-6 fats are considered to have risk of high blood pressure., 8. Foods such as walnuts, flaxseeds, chia seeds, soyabeans,, cod liver oil are rich source of Omega- 3 fatty acids.
Page 4 :
chemistry notes by azeem Sir, , joint my Telegram channel-https://t.me/stateboard11, , class 11 maharashtra notes, , Si, r, , v. Antioxidants as food additives :, 1. An antioxidant is a substance that delays the onset of oxidation, or slows down the rate of oxidation of food stuff., 2. It is used to extend the shelf life of food., 3. Antioxidants react with oxygen-containing free radicals and, thereby prevent oxidative rancidity., 4. For example, vitamin E (tocopherol) is a very effective natural, antioxidant which is added to pack edible oils., 5. The phenolic OH group in its structure is responsible for its antioxidant activity, while the long chain of, saturated carbons makes it fat soluble., 6. It is found in foods such as wheat germ, nuts, seeds,, green leafy vegetables and oils like safflower oil., 7. For economic reason synthetic antioxidants are used as, additives to increase the shelf-life of packed foods., 8. Common structural units found in synthetic antioxidants, are phenolic OH group and tertiary butyl group., 9. For example BHT, which is 3,5 -di-tertbutyl-4hydroxytoluene., , Az, , ee, m, , 10. A chemical which interacts with biomolecules such as carbohydrates, lipids, proteins and nucleic acid and, produces a biological response is called drug., 11. A drug having therapeutic and useful biological response is used as medicine., 12. A medicine contains a drug as its active ingredient., 13. Besides it contains some additional chemicals which make the drug suitable for its use as medicine., 14. Medicines are used in diagnosis, prevention and treatment of a disease., 15. Drugs being foreign substances in a body, often give rise to undesirable, adverse side effects., 16. Drug design is an important branch of medicinal chemistry which aims at synthesis of new molecules having, better biological response., 17. There is an increasing trend in the current research in medicinal chemistry to take cognizance of traditional, medical knowledge such as Ayurvedic medicine or natural materials to discover new drugs., 18. In this section, we consider some simple compounds having medicinal properties and active ingredients of some, natural materials those are traditionally known to possess medicinal properties., 16.2.1 Analgesics and antipyretics, 1. 'Algesis' is a Greek word meaning 'feeling of pain.', 2. Drugs which give relief from pain are called analgesics., 3. About half of the analgesics are anti-inflammatory drugs, which kill pain by reducing inflammation or swelling., 4. Antipyretics are used to reduce fever., 5. Pain-killing and fever reducing properties of an extract of bark of willow plant (commonly found in Europe) have, been known for centuries., 6. In nineteenth century its active ingredient, salicylic acid (2-hydroxybenzoic acid) was isolated and purified., 7. The compound aspirin which is acetyl derivative of salicylic acid was found to have a fewer side effects than, salicylic acid., 8. It is one of the most widely used analgesic to date., 9. It however, retains stomach irritating side effects of salicylic acid., 10. A less problematic pain-killer is paracetamol, which is a phenol.
Page 5 :
chemistry notes by azeem Sir, , joint my Telegram channel-https://t.me/stateboard11, , class 11 maharashtra notes, , 16.2.2 Antimicrobials :, 1. The name antimicrobial is an umbrella term for any drug that inhibits or kills microbial cells that include, bacteria, fungi and viruses., 2. Disinfectants are non-selective antimicrobials, which kill a wide range of microorganisms including bacteria., 3. Disinfectants are used on non-living surfaces for example, floors, instruments, sanitary ware and many others., 4. Antiseptics are used to sterilize surfaces of living tissue when the risk of infection is very high, such as during, surgery, on wounds and so on., 5. Antibiotics are a type of antimicrobial designed to target bacterial infections within or on the body., , ee, m, , Si, r, , a. Antiseptics and disinfectants :, 1. Commonly used antiseptics include inorganics like iodine and boric acid or organics like iodoform and some, phenolic compounds., 2. Tincture of iodine (a 2 β 3 percent solution of iodine in alcohol- water mixture) and iodoform serve as powerful, antiseptics and find use to apply on wounds., 3. A dilute aqueous solution of boric acid is a weak antiseptic used for eyes., 4. Various phenols are used as antiseptics and disinfectants., 5. A dilute aqueous solution of phenol (known as carbolic acid) was one, of the first antiseptic used in medicine in the late nineteenth century., 6. It was however, found to be corrosive., 7. Many chloro derivatives of phenols have been realized as more, potent antiseptics than the phenol itself., 8. They can be used with much lower concentrations, which reduce, their corrosive effects., 9. Two of the most common phenol derivatives in use are, trichlorophenol (TCP) and chloroxylenol., 10. The latter is the active ingredient ( 4.8% W/V ) of the popular, antiseptic dettol., 11. The other ingredients of dettol are isopropyl alcohol, pine oil, castor oil soap, caramel and water., 12. Thymol obtained from oil of thyme (a spice plant) is an excellent nontoxic antiseptic., 13. The p-chlorobenzyl phenol is used as disinfectant in all purpose cleaners., , Az, , b. Antibiotics :, 1. Antibiotics are purely synthetic or obtained from microorganisms, (bacteria, fungi or molds)., 2. Arsenic compounds were known to be highly poisonous to humans since, long., 3. Paul Ehrlich, German bacteriologist investigated arsenic based organic, compounds in order to produce less toxic substances for the treatment of, syphilis., 4. He discovered the first effective treatment of syphilis, the synthetic, antibiotic named salvarsan., 5. He was awarded the Nobel prize for medicine (1908) for this discovery., 6. Ehrlich noticed similarly in the structures of salvarsan and azodyes., 7. With further investigations he succeeded in synthesis of an effective, diazo antibacterial, pronitosil, in 1932., 8. Subsequently it was discovered that prontosil gets converted into a simpler, compound sulphanilamide in our body., 9. This gave further direction to research in drug design which led to discovery, of a wide range of sulpha drugs, analogues to sulphanilamide., 10. One of the most effective being sulphapyridine.
Page 6 :
chemistry notes by azeem Sir, , joint my Telegram channel-https://t.me/stateboard11, , class 11 maharashtra notes, , 11. Antibiotics can be of three types : broad spectrum (effective against wide range of bacteria), narrow, spectrum (effective against one group of bacteria) or limited spectrum (effective against single organism)., 12. A disadvantage of broad spectrum antibiotics is that they also kill the useful bacteria in the alimentary canal., 13. Today many broad spectrum, narrow spectrum and limited spectrum antibiotics are known., 14. They are synthetic, semisynthetic or of microbial origin., 15. Since ancient times, in India, many grandma remedies are practiced for curing ailments., 16. The ancient medicinal system of India has documented medicinal uses of innumerable Indian plants., 17. There is an increasing trend in the modern medicinal chemistry to make use of the traditional knowledge from, various parts of world, to isolate active ingredients from medicinal plants and further develop new drugs., 18. Table ππ. π enlists a few medicinal plants, their medicinal property and active ingredients therein., Table 16.2 : Active ingredients of some medicinal plants, Medicinal property, Name and the structure of Active ingredient, Antiseptic, , Analgesic, , Cinnamon, , Antimicrobials for colds, , Clove, , Antimicrobial, Analgesic, , Indian gooseberry, (Amla), , Az, , Citrus fruits, , ee, m, , Wintergreen, , Si, r, , Plant, Turmeric, , Antioxidant, , Antidiabetic, Antimicrobial,, Antioxidant
Page 7 :
chemistry notes by azeem Sir, , joint my Telegram channel-https://t.me/stateboard11, , class 11 maharashtra notes, , 16.3 Cleansing Agents :, 1. Cleansing agents are substances which are used to remove stain, dirt or clutter on surfaces., 2. They may be natural or synthetically developed., , Si, r, , 16.3.1 Types of cleansing agents :, Commercially cleansing agents are mainly of two types depending upon chemical composition :, soaps and, synthetic detergents., a. Soaps:, 1. Soaps are sodium or potassium salts of long chain fatty acids., 2. They are obtained by alkaline hydrolysis of natural oils and fats with NaOH or KOH. This is called saponification, reaction., 3. Chemically oils are triesters of long chain fatty acids and propan-1, 2,3-triol commonly known as glycerol or, glycerin., 4. Saponification of oil produces soap and glycerol., , Az, , ee, m, , 5. The quality of soap depends upon the nature of oil and alkali used., 6. Potassium soaps are soft to skin., 7. Therefore toilet soaps are prepared by using better grades of oil and KOH., 8. Care is taken to remove excess of alkali. Laundary soaps are made using NaOH., 9. These also contain fillers like sodium rosinate (a lathering agents), sodium silicate, borax, sodium and trisodium, phosphate., 10. Hard water and soup : Soups are water soluble., 11. They form scum in hard water and become inactive., 12. This is because hard water contains dissolved salts of calcium and magnesium, which react with soap,, precipitating calcium or magnesium salt of fatty acid (scum) which sticks to fabric., ππ β πππππ(ππͺ) + ππππ₯π (ππͺ) βΆ, (π β πππ)π ππ(π¬) + πππππ₯(ππͺ), 13. Washing soda (Na 2 CO3 ) precipitates the dissolved calcium salts as carbonate and helps the soap action by, softening of water., b. Synthetic detergents :, 1. Synthetic detergents are man made cleansing agents designed to use even in hard water., 2. There are three types of synthetic detergents, anionic detergents, cationic detergents and nonionic, detergents., i. Anionic detergents are sodium salts of long chain alkyl, sulphunic acids or long chain alkyl substituted benzene sulphonic, acids., ii. Cationic detergents are quaternary ammonium salts having, one long chain alkyl group., iii. Nonionic detergents are ethers of polyethylene glycol with, alkyl phenol or esters of polyethylene glycol with long chain, fatty acid., Table ππ. π displays some syntheic detergents.
Page 8 :
chemistry notes by azeem Sir, , joint my Telegram channel-https://t.me/stateboard11, , class 11 maharashtra notes, , 3. Mechanism of cleansing action :, Soaps and detergents bring about cleansing of dirty, greasy surfaces by the same mechanism., 4. Dirt is held at the surface by means of oily matter and, therefore, cannot get washed with water., 5. The molecules of soaps and detergent have two parts., 6. One part is polar (called head) and the other part is long nonpolar chain of carbons (called tail)., 7. The polar head (hydrophilic) can dissolve in water which is polar solvent., 8. The nonpolar tail (hydrophobic) dissolve in oil/fat/grease., 9. The molecules of soap/detergent are arranged around the oily droplet such that the nonpolar tail points towards, the central oily drop while the polar head is directed towards the water. (see Fig. 16.2), 10. Thus, micelles of soap/detergent are formed surrounding the oil drops, which are removed in the washing, process., , Non ionic detergent, , Use, Household detergent, additive, in toothpaste, , Hair conditioner, germicide, , Si, r, , Non ionic detergent, , πππ (πππ )ππ β π β (πππ )π ππ« β, (ethyltrimethyl ammonium bromide), , πππ (πππ )ππ β πππ(πππ πππ π)π§πππ πππ ππ, (an ester), , ee, m, , Cationic detergent, , (sodium lauryl sulphate), β, πππ (πππ )ππ πππ πππβ, π ππ, , Az, , Type, Anionic detergent, , Table 16.3 : Synthetic detergents, Example, , Liquid dish wash, , Liquid detergent
Page 9 :
chemistry notes by azeem Sir, , joint my Telegram channel-https://t.me/stateboard11, , class 11 maharashtra notes, , Exercises, Choose correct option, A. Oxidative Rancidity is ...... reaction, a. addition, b. subtitution, c. Free radical d. combination, , C. Aspirin is chemically named as, a. Salicylic acid, b. acetyl salicylic acid, c. chloroxylenol, d. thymol, , E. Arsenic based antibiotic is, a. Azodye, b. prontosil, c. salvarsan, d. sulphapyridine, , ee, m, , D. Find odd one out from the following, a. dettol, b. chloroxylenol, c. paracetamol, d. trichlorophenol, , Si, r, , B. Saponification is carried out by, a. oxidation, b. alkaline hydrolysis, c. polymarisation, d. Free radical formation, , Az, , 1, , F. The chemical used to slow down the browning action of cut fruit is, a. SO3, b. SO2, c. H2 SO4, d. Na 2 CO3, G. The chemical is responsible for the rancid flavour of fats is, a. Butyric acid, b. Glycerol, c. Protein, d. Saturated fat, H. Health benefits are obtained by consumption of, a. Saturated fats, b. trans fats, c. mono unsaturated fats, d. all of these
Page 10 :
chemistry notes by azeem Sir, , joint my Telegram channel-https://t.me/stateboard11, , class 11 maharashtra notes, , 2. Explain the following :, A. Cooking makes food easy to digest., B. On cutting some fruits and vegetable turn brown., C. Vitmin E is added to packed edible oil., D. Browning of cut apple can be prolonged by applying lemon juice., E. A diluted solution (4.8%w/v) of 2,4,6-trichlorophenol is employed as antiseptic., F. Turmeric powder can be used as antiseptic., , Az, , ee, m, , Si, r, , 3. Identify the functional grops in the following molecule :
Page 11 :
chemistry notes by azeem Sir, , 4, , joint my Telegram channel-https://t.me/stateboard11, , class 11 maharashtra notes, , Give two differences between the following, A. Disinfectant and antiseptic, B. Soap and synthetic detergent, C. Saturated and unsaturated fats, D. Rice flour and cooked rice, , 5, , Match the pairs., A group, A. Paracetamol, B. Chloramphenicol, C. BHT, detergent, D. Sodium stearate, , B group, a. Antibiotic, b. Synthetic, c. Soap, d. Antioxidant, e. Analgesic, , Name two drugs which reduce body pain., , 7, , Explain with examples, A. Antiseptics, , C. Cationic detergents, D. Anionic detergent, , Az, , E. Non-ionic detergents, , ee, m, , B. Disinfectant, , Si, r, , 6, , 8. Explain : mechnism of cleansing Action of soap with flow chart., 9. What is meant by broad spectrum antibiotic and narrow spectrum antibiotics?, 10. Answer in one senetence, , A. Name the painkiller obtained from acetylation of salicyclic acid., B. Name the class of drug often called as painkiller., C. Who discovered penicillin?, D. Draw the structure of chloroxylenol and salvarsan., E. Write molecular formula of Butylated hydroxy toulene., F. What is the tincture of iodine ?, G. Draw the structure of BHT.
Page 12 :
chemistry notes by azeem Sir, , joint my Telegram channel-https://t.me/stateboard11, , class 11 maharashtra notes, , H. Write a chemical equation for saponification., I. Write the molecular formula and name of, , 11 Answer the following, A. Write two examples of the following., a. Analgesics, c. Antiseptics d. Antibiotics, e. Disinfectant, , Az, , ee, m, , Si, r, , B. What do you understand by antioxidant ?