TS Inter 2nd Year Chemistry Study Material Chapter 10 Chemistry in Everyday Life

Telangana TSBIE TS Inter 2nd Year Chemistry Study Material 10th Lesson Chemistry in Everyday Life Textbook Questions and Answers.

TS Inter 2nd Year Chemistry Study Material 10th Lesson Chemistry in Everyday Life

Very Short Answer Questions (2 Marks)

Question 1.
What are drugs ?
Answer:
Drugs are chemicals of low molecular masses (~ 100 to 500 u), that interact with macro-molecular targets and produce a biological response.

Question 2.
When are the drugs called medicines ?
Answer:
The drugs are called medicines when their biological response is therapeutic and useful.

Question 3.
Define the term chemotherapy.
Answer:
Chemotherapy is defined as the use of chemicals for therapeutic effect.

Question 4.
Name the macromolecules that are chosen as drug targets.
Answer:
Carbohydrates, lipids, proteins and nucleic acids are the macromolecules that are chosen as drug targets.

Question 5.
What are enzymes and receptors ?
Answer:
Proteins which perform the role of biological catalysts in the body are called enzymes. Receptors are proteins that are crucial to body’s communication process.

Question 6.
Which forces are involved in holding the drug to the active site of enzymes ?
Answer:
Forces such as ionic bonding, hydrogen bonding, van der Waals interaction or dipole – dipole interaction are involved in holding the drug to the active site of enzymes.

Question 7.
What are enzyme inhibitors ?
Answer:
Drugs which can block the binding site of the enzyme and prevent the binding of substrate or can inhibit the catalytic activity of the enzyme are called enzyme inhibitors.

Question 8.
What is allosteric site ?
Answer:
Allosteric site is a site in the enzyme that is different from the active site. The binding of the inhibitor at the allosteric site changes the shape of the active site in such a way the substrate cannot recognise it.

Question 9.
What are antagonists and agonists ?
Answer:
Drugs that bind to the receptor site and inhibit its natural function are called antagonists. Drugs that mimic the natural messenger by switching on the receptor are called agonists.

Question 10.
Why do we need to classify the drugs in different ways ?
Answer:
The classification of drugs in different ways is useful to the doctors because it provides them the whole range of drugs available for the treatment of a particular disease.

Question 11.
What are antacids ? Give example. [IPE 14]
Answer:
Drugs which are used for the treatment of over production of acid in the stomach (acidity) are called antacids.
Ex : Ranitidine (Zantac), Omeprazole, Lansoprazole.

Question 12.
What are antihistamines ? Give example.
Answer:
Drugs which interfere with the natural action of histamine by competing with histamine for binding sites of receptor where histamine exerts its effects are called antihistamines.
Ex : Brompheniramine, Dincetane, terfenadine.

Question 13.
While antacids and antiallergic drugs interfere with the function of histamines, why do not these interfere with the function of each other ?
Answer:
Antacids and antiallergic drugs work on different receptors hence they do not interfere with each other’s function.

Question 14.
What are tranquilizers ? Give example.
Answer:
Tranquilizers are a class of chemical compounds used for the treatment of stress and mild or even severe mental diseases.
Ex: Iproniazid, Luminol, Second, Babituric acid.

Question 15.
What are barbiturates ?
Answer:
Derivatives of barbituric acid which con-stitute an important class of tranquilizers are called barbiturates.
Ex: veronal, amytal and seconal.

Question 16.
What are analgesics? How are they classified ?
Answer:
Drugs which reduce or abolish pain without causing disturbances of nervous system like impairment of consciousness, mental confusion, in coordination, paralysis etc., are called analgesics Analgesics are classified as

1. Narcotic analgesics and
2. Non – Narcotic analgesics.

Question 17.
What are narcotic analgesics ? Give example.
Answer:
Morphine and many of its homologues, when administered in medicinal doses, relieve pain and produce sleep. These are called narcotic analgesics because they have addictive properties.
Ex : Heroin, Morphine, Codeine.

Question 18.
What are non – narcotic analgesics ? Give example.
Answer:
Analgesics having no addictive properties are called non – narcotic analgesics.
Ex: Aspirin, Ibuprofen.

Question 19.
What are antimicrobials ?
Answer:
Drugs that tend to destroy / prevent development or inhibit the pathogenic action of microbes such as bacteria, fungi, virus or any other parasites are called antimicrobials.
Ex : Lysozyme, Lactic acids, etc.

Question 20.
What are antibiotics ? Give example. [Mar. 2018, 16-A.P.]
Answer:
Antibiotics are substances produced wholly or partly by chemical synthesis which in low concentrations inhibit the growth or destroy micro organisms by intervening in their metabolic processes.
Ex : Penicillin, Chloramphericol, sulphadiazine.

Question 21.
What are antiseptics ? Give example. [AP Mar. 19; (AP & TS 15)]
Answer:
Antiseptics are chemicals which either kill or prevent the growth of microorganisms.
Ex: Furacin, Dettol, Bithional.

Question 22.
What are disinfectants ? Give example.
Answer:
Disinfectants are chemicals which either kill or prevent the growth of microorganisms.
Ex: 1% solution of phenol, formalin (4% ag of soln of formaldehyde), 0.3 ppm chlorine.

Question 23.
Name a substance which can be used as an antiseptic as well as disinfectant.
Answer:
Phenol (0.2 % phenol antiseptic and 1% phenol as dis infectant).

Question 24.
What is the difference between antiseptics and disinfectants ?
Answer:
Antiseptics are applied to living tissues such as wounds, cuts, ulcers and diseased skin surfaces whereas disinfectants are applied to inanimate objects such as floors, drainage system, instruments etc.

Question 25.
What are the main constituents of dettol ?
Answer:
Chloroxylenol and terpineol are the main constituents of dettol.

Question 26.
What is tincture of iodine ? What is its use ?
Answer:
2-3% solution of iodine in alcohol – water mixture is known as tincture of iodine. It is used as an antiseptic.

Question 27.
What are antifertility drugs ? Give example.
Answer:
Drugs used to control population are called antifertility drugs.
Ex : Norethindrone, Mifepristone, Ethynyl estradiol.

Question 28.
Why chemicals are added to food ?
Answer:
Chemicals are added to food for

1. their preservation
2. enhancing their appeal and
3. adding nutritive value.

Question 29.
Name different categories of food additives.
Answer:
The main categories of food additives are:

1. Food colours
2. Flavours and sweeteners
3. Fat emulsifiers and stabilising agents
4. Flour improvers – antistaling agents and bleaches
5. Antioxidants
6. Preservatives
7. Nutritional supplements

Question 30.
What are artificial sweetening agents ? Give example.   [A.P. 16, 15; T.S. 15]
Answer:
Artificial sweetening agents are chemicals, used in place of sugar, which decrease the intake of calories and at the same time several times sweeter than sucrose.
Ex: Aspartame

Question 31.
Why do we require artificial sweetening agents ?
Answer:
Natural sweeteners e.g., sucrose add to calorie intake. Hence diabetic persons and ’ people who need to control intake of calories require artificial sweeteners.

Question 32.
Why is the use of aspartame limited to cold foods and drinks ?
Answer:
Use of aspartame is limited to cold foods and drinks because it is unstable at cooking temperature.

Question 33.
Name the sweetening agent used in the preparation of sweets for a diabetic patient
Answer:
Saccharin

Question 34.
What problem does arise in using alitame as artificial sweetener ?
Answer:
Alitame is a high potency sweetener and control of sweetness of food is difficult while using it.

Question 35.
What are food preservatives? Give example.
Answer:
Food preservatives are substances which prevent spoilage of food due to microbial growth.
Ex : Sodium benzoate, Sodium, metabisulphate.

Question 36.
Name two most familiar antioxidants used as food additives.
Answer:
Butylated hydroxy toluene (BHT) and butylated hydroxy anisole (BHA) are the two most familiar antioxidants used as food additives.

Question 37.
What is saponification ?
Answer:
Soaps containing sodium salts are formed by heating fat (i.e., glyceryl ester of fatty acid) with aqueous sodium hydroxide solution. This reaction is known as saponification.

Question 38.
What are soaps chemically ?
Answer:
Soaps are sodium or potassium salts of long chain fatty acids, e.g., oleic and palmitic acids.

Question 39.
Why do soaps not work in hard water ?
Answer:
Hard water contains calcium and magnesium ions. These ions form insoluble calcium and magnesium soaps respectively when sodium or potassium soaps are dissolved in hard water.

Question 40.
What are synthetic detergents ?
Answer:
Synthetic detergents are cleansing agents which have all the properties of soaps, but which actually do not contain any soaps.

Question 41.
What is the difference between a soap and a synthetic detergent ? [(Mar. 2018 AP)(IPE: 14) ]
Answer:
Soap does not work in hard water whereas a synthetic detergent can be used both in soft and hard water.

Question 42.
How are synthetic detergents better than soaps ?
Answer:
Synthetic detergents with straight chain of hydrocarbons are biodegradable and hence prevent pollution.

Question 43.
Name the different categories of synthetic detergents.
Answer:
Synthetic detergents are classified into three categories.

1. Anionic detergents
2. Cationic detergents and
3. Non – ionic detergents.

Question 44.
Can you use soaps and synthetic detergents to check the hardness of water ?
Answer:
No

Question 45.
If water contains dissolved calcium hydrogen carbonate, out of soaps and synthetic detergents which one will you use for cleaning clothes and why ?
Answer:
If water contains calcium ions, these ions form insoluble calcium soap when sodium or potassium soaps are dissolved in water. This insoluble soap separates as scum in water and is useless as cleansing agent. In such a case a synthetic detergent is preferred as it gives foam even in the presence of calcium ions.

Short Answer Questions (4 Marks)

Question 46.
Explain the term target molecules or drug targets as used in medicinal chemistry.
Answer:
Drugs usually interact with biomolecules such as carbohydrates, Lipids, proteins and nucleic acids. These are called target molecules or drug targets.

Question 47.
Explain the catalytic action of enzymes as drug targets.
Answer:
The enzymes perform two major functions in their catalytic activity.
The first function of an enzyme is to hold the substrate for a chemical reaction. Active sites of enzymes hold the substrate molecule in a suitable position, so that it can be attacked by the reagent effectively. Substrates bind to the active site of the enzyme through a variety of interactions such as ionic bonding, hydrogen bonding, van der Waals interaction or dipole – dipole interaction.

The second function of an enzyme is to provide functional groups that will attack the substrate and carryout chemical reaction.

Question 48.
Explain the drug – enzyme interaction.
Answer:
Drugs inhibit the activities of enzymes. They can block the binding site of the enzyme and prevent the binding of substrate or can inhibit the catalytic activity of the enzyme. Such drugs are called enzyme inhibitors.

Drugs inhibit the attachment of substrate on active site of enzymes in two different ways.

1. Drugs compete with the natural substrate for their attachment on the active sites of enzymes.
2. Some drugs bind to a different site of the enzyme called allosteric site. This binding of inhibitor at allosteric site changes the shape of the active site in such a way that substrate cannot recognise it.

Question 49.
Why are cimetidine and ranitidine better antacids than sodium hydrogen carbonate or magnesium hydroxide or aluminium hydroxide.
Answer:
Antacids such as sodium hydrogen carbo-nate or magnesium hydroxide or aluminium hydroxide control only the symptoms but not the cause. On the otherhand cimetidine and ranitidine prevent the interaction of histamine with the receptors present in the stomach wall. This results in release of lesser amount of acid. Hence these drugs are better antacids.

Question 50.
Low level of noradrenaline is the cause of depression. What type of drugs are needed to cure this problem ? Name two drugs.
Answer:
Antidepressant drugs, which inhibit the enzymes that catalyse the degradation of noradrenaline are needed to cure the pro-blem of depression.
Ex : Iproniazid and phenelzine are antidepressant drugs.

Question 51.
What are analgesics? How are they classified ? Give examples. [Mar. 2018 TS)(AP 15)]
Answer:
Drugs which reduce or abolish pain without causing disturbances of nervous system like impairment of consciousness, mental confusion, incoordination, paralysis etc., are called analgesics. Analgesics are classified as

1. Non – narcotic (non – addictive) analgesics and
2. Narcotic drugs.

Non – Narcotic analgesics: Aspirin and paracetamol belong to this class of analgesics. These drugs relieve pain and have other effects such as reducing fever and preventing platelet coagulation.
Ex : Morphine, Codine.

Narcotic analgesics: Morphin and many of its homologues belong to this category. When administered in medicinal doses they relieve pain and produce sleep.
Ex: Aspirin, Ibuprofen.

Question 52.
What are different types of microbial drugs ? Give one example for each.
Answer:
Antibiotics, antiseptics and disinfectants are different types of microbial drugs.
Antibiotics : Ex: Penicillin
Antiseptics : Ex: Furacin
Disinfectants : Ex: \% solution of phenol.

Question 53.
Write the characteristic properties of antibiotics.
Answer:

1. An antibiotics must be a product of metabolism.
2. An antibiotic should be effective in low concentrations.
3. An antibiotic should retard the growth or survival of microorganisms.
4. An antibiotic should be synthetic substance produced as a structural analogue of naturally occurring antibiotic.

Question 54.
What is meant by the term ‘broad spectrum antibiotics’ ? Explain.
Answer:
Antibiotics which kill or inhibit a wide range of gram – positive and gram – negative bacteria are said to be broad spectrum antibiotics.

Antibiotics which are effective mainly against gram positive or gram negative bacteria are narrow spectrum antibiotics. Those effective against a single organism or disease are referred to as limited spectrum antibiotics.

Question 55.
What are broad spectrum and narrow spectrum antibiotics ? Give one example for each.
Answer:
Antibiotics which kill or inhibit a wide range of gram – positive and gram – negative bacteria are called broad spectrum antibiotics.
Ex : Chloramphenicol, Ampicillin, Amoxycilin.

Antibiotics which are effective mainly against gram – positive or gram – negative bacteria are called narrow spectrum antibiotics.
Ex: Penicillin G

Question 56.
Write notes on antiseptics and disinfectants. [TS 15]
Answer:
Antiseptics and disinfectants are chemicals which either kill or prevent the growth of microorganisms.

Antiseptics are applied to the living tissues such as wounds, cuts, ulcers and diseased skin surfaces. Ex: Furacin, soframicine, dettol.

Disinfectants are chemicals which either kill or prevent the growth of microorganisms. These are applied to inanimate objects such as floors, drainage systems, instruments etc. Ex : 1 % solution of phenol.

Same substance can act as an antiseptic as well as disinfectant by varying concentration. For example 0.2% solution of phenol is an antiseptic while its 1% solution is disinfectant.

Question 57.
How do antiseptics differ from disinfectants ? Does the same substance be used as both ? Give one example for each.
Answer:
Antiseptics differ from disinfectants in the manner of application. Antiseptics are applied to the living tissues such as wounds, cuts, ulsers and diseased skin surfaces where as disinfectants are applied to inanimate objects such as floors, drainage system, instruments etc.

Same substance can be used as an anti-septic as well as disinfectant by varying concentration.
Ex : 0.2% solution of phenol is an anti-septic while its 1% solution is disinfectant.

Question 58.
What are the main categories of food additives ?
Answer:
The main categories of food additives are:

1. Food colours
2. Flavours and sweeteners
3. Fat emulsifiers and stabilising agents
4. Flour improvers – antistaling agents and bleaches
5. Antioxidants
6. Preservatives
7. Nutritional supplements such as minerals, vitamins and amino acids.

Question 59.
Write notes on antioxidants in food.
Answer:
Antioxidants are important food additives. They help in food preservation by retarding the action of oxygen in food. These are more reactive towards oxygen than the food material they are protecting.

Butylated hydroxytoluene (BHT) and butylated hydroxy anisole (BHA) are the two most familiar antioxidants. Sometimes BHT and BHA are mixed with citric acid or ascorbic acid to produce more effect. Sulphur dioxide and sulphite are used as antioxidants for wine, beer, sugar syrup, cut, peeled or dried fruits and vegetables.

Question 60.
Name different types of soaps.
Answer:
There are different types of soaps such as

1. Toilet soaps
2. Soaps that float in water
3. Transparent soaps
4. Medicated soaps
5. Shaving soaps
6. Laundry soaps
7. Soap granules
8. Soap powders
9. Scouring soaps

Question 61.
Explain the following terms with suitable examples.
i) Cationic detergents
ii) Anionic deter-gents
iii) Non – ionic detergents
Answer:
i) Cationic detergents: Cationic detergents are quartemary ammonium salts of amines with acetates, chlorides or bromides as anions. Cationic part possesses a long hydrocarbon chain and a positive charge on nitrogen atom.
Ex:
Cetyl trimethyl ammonium bromide is a popular cationic detergent. It is used in hair conditioners.

ii) Anionic detergents: Anionic detergents are sodium salts of sulphonated long chain alcohols or hydrocarbons. In these detergents, the anionic part of the molecule is involved in the cleansing action. Sodium salts of alkyl benzene sulphonates are an important class of anionic detergents.
Ex: Sodium dodecylbenzene sulphonate.

iii) Non – ionic detergents: Non – ionic detergents do not contain any ion in their constitution.
Ex : A non – ionic detergent is formed when stearic acid reacts with polyethylene glycol.
CH₃ (CH₂)₁₆ COOH + HO (CH₂ CH₂O)_n
CH₂ CH₂OH CH₃ (CH₂)₁₆ COO (CH₂ CH₂O)_n CH₂ CH₂OH
Liquid dish washing detergents are non-ionic type. Just like soaps, these detergents remove grease and oil by micelle formation.

Question 62.
What are biodegradable and non – biodegradable detergents ? Give one example for each.
Answer:
Detergents which are metabolised by natural bacteria are called biodegradable detergents. On the otherhand, detergents which are not degraded by bacteria easily leading to their accumulation are called non – biodegradable detergents. Branched chain detergents are non – biodegradable and unbranched hydrocarbon detergents are biodegradable.
Ex:

Question 63.
Explain the cleansing action of soaps.
Answer:
Soaps are sodium or potassium salts of fatty acids. They may be represented as \(2 \mathrm{RO} \overline{\mathrm{O}}\)\(\stackrel{+}{\mathrm{N}}\)a.
Ex: Sodium stearate, CH₃ (CH₂)₁₆ \(\mathrm{CO} \overline{\mathrm{O}}\stackrel{+}{\mathrm{N}}\)a. When dissolved in water the soap dissociates into \(\mathrm{RO} \overline{\mathrm{O}}\) and \(\stackrel{+}{\mathrm{N}}\)a ions. The \(\mathrm{RO} \overline{\mathrm{O}}\) ions consist of two parts – a long hydrocarbon chain R (also called non – polar tail) which is hydrophobic (water repelling), and a polar group \(\mathrm{CO} \overline{\mathrm{O}}\) (also called polar ionic head) which is hydrophilic (water loving).

Long chain carboxylate ions do not exist as individual ions in aqueous solution, instead they arrange themselves in spherical clusters called micelles. Each micelle contains 50-100 long – chain carboxylate ions. The polar carboxylate end of each ion is on the outside of the micelle because of its attraction for water.

The non – polar end is in the interior of the miscelle to minimise its contact with water. Because the surface of the miscelle is negatively charged, the individual miscelles repel each other instead of clustering to form larger agregates. The cleansing action of soap results from the fact that non – polar oil molecules, which carry dirt, dissolve in the non- polar interior of the miscelle and are carried away with the soap during rinsing.

Question 64.
Label the hydrophillic and hydrophobic parts in the following compounds.
i) CH₃ (CH₃)₁₀ CH₂ OSO₃ ^–Na⁺
ii) CH₃ (CH₂)₁₅ N⁺ (CH₂)₃ Br^–
iii) CH₃ (CH₂)₁₆ COO(CH₂CH₂O)_nCH₂CH₂ OH
Answer:

Question 65.
Draw the structures of the following.
i) Serotonin
ii) Bithionol
iii) Chloramphenicol
iv) Saccharin
Answer:

Long Answer Questions (8 Marks)

Question 66.
Describe the classification of drugs into different classes.
Answer:
Drugs are classified on the basis of various criteria.
i) On the basis of pharmacological effect:
Drugs can be classified on the basis of their pharmacological effect. For example, analgesics are pain killers and antiseptics kill or stop the growth of microorganisms.

ii) On the basis of drug action:
Based on the action of drugs on particular biochemical processes they are classified as antihistamines, sedatives, cardiovascular drugs etc. All antihistamines inhibit the action of the compound, histamine which causes inflammation in the body.

iii) On the basis of chemical structure:
Drugs classified on the basis of structure share common structural features and have similar pharmacological activity. For example, sulphonamides have common structural feature given below.

iv) On the basis of molecular targets:
Drugs usually interact with biomolecules like carbohydrates, lipids, proteins, nucleic acids etc. These biomolecules are called drug targets or target molecules. Drugs with common structural features may have the same mechanism of action on targets.

Question 67.
Describe briefly the therapeutic action of different classes of drugs.
Answer:
Therapeutic action of different classes of drugs:

Antacids :
Over production of acid in the stomach causes irritation and pain. Antacids are used for the treatment of acidity. Antacids such as sodium bicarbonate or a mixture of aluminium and magnesium hydroxides control only the symptoms and not the cause. Drugs such as cimetidine (Tegamet) and ranitidine (Zantac) prevent the interaction of histamine with the receptors present in the stomach wall resulting in the release of less amount of acid.

Antihistamines :
Drugs such as brom- phenaramine (Dimetapp) and terfenadine (seldane) act as antihistamines. They interfere with the natural action of histamine by competing with histamine for binding sites of receptor where histamine exerts its effect.

Neurologically active drugs:
Tranquilizers and analgesics are neurologically active drugs. These affect message transfer mechanism from nerve to receptor. Tranquilizer are a class of compounds used for the stress and mild or even severe mental diseases. These relieve anxiety, stress, irri-tability or excitement by inducing a sense of well being.

If the level of noradrenaline is low the person suffers from depression. In such situations antidepressant drugs such as iproniazid and phenelzine are used. These drugs inhibit the enzymes which catalyse the degradation of noradrenaline and counteract the effect of depression.

[Mar. 2018-TS]
Analgesics:
Analgesics reduce or abolish pain without causing disturbances of nervous system. They are two classes of analgesis i) Non -narcotic (non addictive) analgesics and ii) Narcotic analgesics. Aspirin and paracetamol are non – narcotic analgesics. Aspirin inhibits the synthesis of chemicals known as prostaglandins which stimulate inflammation in the tissue and cause pain.

Morphine and many, of its homologues are narcotic analgesics. When administered in medicinal doses they relieve pain and produce sleep.

Antimicrobials:
An antimicrobial tends to destroy / prevent development or inhibit pathogenic action of microbes such as bac-teria, fungi, virus or other parasites. Anti-biotics, antiseptics and disinfectants are antimicrobial drugs.

Antibiotics in low concentrations inhibit the growth or destroy microorganisms by intervening in their metabolic process.

Broad spectrum antibiotics like chloramphenicol kill or inhibit a wide range of gram – positive and gram – negative bacteria. Narrow spectrum antibiotics like penicillin G are effective mainly against gram – positive or gram – negative bacteria.

Antiseptics and disinfectants :
These are chemicals which either kill of prevent the growth of microorganisms. Antiseptics are applied to the living tissues such as wounds, cuts and diseased skin surfaces.
Ex: Furacin.

Disinfectants are applied to inanimate objects such as floors, drainage system, instruments etc. Some substances can act as antiseptic as well as disinfectant by varying concentration.

Antifertility drugs :
These drugs are used to control population. Birth control pills essentially contain a mixture of estrogen and progesterone derivatives. Progesterone suppresses ovulation.

Question 68.
Write an essay on antimicrobials.  [TS Mar. 19]
Answer:
Diseases in human beings and animals may be due to the action of a variety of microorganisms like bacteria, virus, fungi and other pathogens.

An antimicrobial tends to destroy / prevent development or inhibit the pathogenic action of microbes selectively. Antibiotics, antiseptics and disinfectants are antimicrobial drugs.

Antibiotics :
Antibiotics are chemical substances produced by microorganisms (bacteria, fungi and mould) which inhibit the growth or destroy microorganisms. To cover synthetic antibiotics the definition for antibiotics is given as “An antibiotic is a substance that is produced wholly or partly by chemical synthesis and in low concentrations inhibits the growth or destroys microorganisms by interfering in their metabolic process.”

Paul Ehrlich developed salvarsan, an arsenic based drug for the treatment of siphilis caused by bacteria, spirochete. He also developed the first effective antibacterial agent, prontosil which was converted into sulphanilamide in the body. Later a large range of sulpha drugs were synthesised.

Despite the success of sulfonamides, the real success in antibacterial therapy began with the discovery of penicillin by Alexander Fleming in 1929.

Antibiotics have either a cidal (killing) effect or a static (inhibitory) effect on microbes. For example, penicillin, amino glycosides and ofloxacin are bactericidal whereas erythromycin, tetracycline and chloramphenicol are bacteriostatic.

The range of bacteria or other micro-organisms that are affected by a certain antibiotic is expressed as its spectrum of action. Broad spectrum antibiotics kill or inhibit a wide range of gram positive and gram negative bacteria. For example, Ampicillin and Amoxycillin are broad spectrum antibiotics. Antibiotics that are effective mainly against gram – positive or gram – negative bacteria are called narrow spectrum antibiotics. Penicillin G has a narrow spectrum.

Antiseptics and disinfectants :
Anti-septics and disinfectants are chemicals which either kill or prevent the growth of microorganisms.

Antiseptics are applied to the living tissues such as wounds, cuts, ulcers and diseased skin surfaces. Ex : Furacin, Soframi- cine etc.

Iodine is a powerful antiseptic. 2-3% solution of iodine in aqueous alcohol is known as tincture of iodine. It is applied on wounds.

Disinfectants are applied to inanimate objects such as floors, drainage system, instruments etc.

1% solution of phenol is used as disinfectant.

Question 69.
Write notes on the following
i) Artificial sweetening agents
ii) Food preservatives
iii) Antioxidants in food.
Answer:
i) Artificial sweetening agents :
Natural sweeteners like sucrose add to calorie intake . Hence artificial sweeteners are used by many people. Orthosulphobenzimide, also called saccharin, is a popular artificial sweetening agent. It is 550 times as sweet as sucrose. It is excreted through urine. It is inert and harmless when taken. It has great value in controlling calories and it is useful to diabetic persons.

Aspartame is the most successful and widely used artificial sweetener. It is about 100 times as sweet as sucrose. Use of aspartame is limited to cold foods and soft drinks because it is unstable at cooking temperature. Alitame is a high potency sweetener about 2000 times sweeter than sucrose. Control of sweetness of food is difficult while using it. Sucralose is similar to sugar in appearance and taste. It is stable at cooking temperature. It is 600 times as sweet as cane sugar.

ii) Food preservatives:
Food preservatives are added to the food to prevent spoilage due to microbial growth. The most commonly used preservatives include table salt, sugar, vegetable oils and sodium benzoate. Salts of sorbic acid and propanoic acid are also used as food preservatives, sodium benzoate is the most important food preservative. It is metabolised by conversion into hippuric acid which in finally excreted in the urine.

iii) Antioxidants in food:
Antioxidants are important food additives. They help in food preservation by retarding the action of oxygen in food. These are more reactive towards oxygen than the food material they are protecting.

Butylated hydroxy toluene (BHT) and butylated hydroxy anisole (BHA) are the two most familiar antioxidants. Sometimes BHT and BHA are mixed with citric ; acid or ascorbic acid to produce a better effect. Sulphur dioxide and sulphite are used as antioxidants for wine, beer, sugar syrup, cut, peeled or dried fruits and vegetables.

Question 70.
Write notes on the following :
i) Soaps
ii) Synthetic detergents.
Answer:
i) Soaps: Soaps are sodium or potassium salts of long chain fatty acids e.g. stearic, oleic and palmitic acids. Soaps containing sodium salts are obtained by heating fats and oils (glyceryl esters of fatty acids) with sodium hydroxide solution. This reaction is known as saponification.

In this reaction esters of fatty acids are hydrolysed and the soap obtained remains in colloidal form. It is precipitated from the solution by adding sodium chloride. Generally potassium soaps are soft to the skin than sodium soaps. These can be prepared by using potassium hydroxide instead of sodium hydroxide.

Different types of soaps are made by using different raw materials. Toilet soaps, transparent soaps, medicated soaps, laundry soaps, shaving soaps, soaps that float on water etc., are different types of soaps.

Soaps do not work in hard water. Hard water contains calcium and magnesium ions. When sodium soaps are dissolved in it, these ions form calcium and magnesium soaps which are insoluble. These insoluble soaps separate as scum. This results in the waste of sodium soap.

Soaps remove grease and oil by micelle formation.

ii) Synthetic detergents:
Synthetic deter-gents are cleansing agents which have all the properties of soaps, but actually do not contain any soap. These can be used both in soft and hard water.

Synthetic detergents are classified into three categories. i) Anionic detergents ii) Cationic detergents and iii) Non – ionic detergents.

Anionic detergents are sodium salts of long chain alcohols or hydrocarbons. These are formed by treating long chain alcohols with concentrated sulphuric acid and neutralising the alkyl hyrogen sulphates formed with sodium hydroxide. Alkyl benzene sulphonates are obtained by neutralising alkyl benzene sulphonic acids with sodium hydroxide. In anionic detergents the anionic part of the molecule is involved in the cleansing action. These are mostly used in household work.
Ex: Sodium lauryl sulphate, sodium dodecyl benzene sulphonate.

Cationic detergents:
Cationic detergents are quarternary ammonium salts of amines with acetates, chlorides or bromides as anions. Cationic part possesses a long hydrocarbon chain and a positive charge on nitrogen atom.
Ex : Cetyltrimethyl ammonium bromide

Non – ionic detergents :
Non – ionic detergents do not contain any ion in their constitution. Liquid dishwashing detergents are non – ionic type. Branched chain detergents are non – biodegradable and unbranched hydrocarbon detergents me biodegradable and hence pollution is prevented.

Intext Questions – Answers

Question 1.
Sleeping pills are recommended by doctors to the patients suffering from sleeplessness but it is not advisable to take in doses without consultation with the doctor. Why ?
Answer:
If sleeping pills are taken in doses higher than those recommended, they may cause harmful effects and act as poisons. Hence, it is not advisable to use them without consulting the doctor.

Question 2.
With reference to which classification has the statement, ‘ranitidine is an antacid’ been given?
Answer:
This statement is given based on the drug action. Ranitidine counteracts the effects of excess acid in the stomach. Hence it is an antacid.

Question 3.
Why do we require artificial sweetening agents?
Answer:
Natural sweeteners like sucrose add to calorie intake. Hence diabetic persons and people who need to control intake of calories require artificial sweetening agents.

Question 4.
Write the chemical equation for preparing sodium soap from glyceryloleate and glyceryl palmitate. Structural formulas of these compounds are given below.
i) (C₁₅H₃₁COO)₃C₃H₅ – glyceryl palmitate
ii) (C₁₇H₃₂COO)₃ C₃H₅ – glyceryl oleate.
Answer:

Question 5.
Following type of non – ionic detergents are present in liquid detergents, emulsifying agents and wetting agents. Label the hydrophilic and hydrophobic parts in the molecule. Identify the functional group(s) in the molecule.

Answer:

b) Functional group: Ethen and alcohol.