CHEMISTRY IN EVERY DAY LIFE [IMPORTANT POINTS TO REMEMBER]

 CHEMISTRY IN EVERY DAY LIFE

IMPORTANT POINTS TO REMEMBER
By   Mukesh  Sharma

Chemicals in medicines:

·         Drugs: Chemical substances used for treatment of diseases and for reducing pain are called drugs or medicines.

·         Chemotherapy: Chemotherapy is the science in which chemicals are used in treatment of diseases due to bacterial invasion. These chemicals destroy the microorganisms without

            Affecting, to any material extent, the tissues (of the host).

·         Classification of Drugs.

Drugs can be classified in several ways.

Based on pharmacological effect.

Drugs ill classified on the basis of their physicological effect on our body e.g., antipyretic drugs reduce temperature of several body whereas antiseptic drugs prevent the growth of micro-organism

Based on a particular biochemical process:

Some drugs affect biochemical processes, e,g., antihistamines drugs supress the action nl histamine which causes inflammation in iliI body.

Based on chemical nature.

Some drugs have effect on the body based on their structural features, e.g., sulpha drugs can supress illness multiplication of micro-organisms like bacteria due to their structure, therefore, they are used as antibacterial.

Based on molecular targets.

They are based on molecular targets like enzymes, receptor of cell, macromolecules like carbohydrate!, proteins, lipids, nucleic acids.

Based on therapeutic action:

• Analgesics: Drugs used for relieving pain e.g.:- Aspirin, codeine, heroin etc.
• Tranquilizers: - Class of chemical compounds used for treatment of stress and mental diseases. Eg: - Luminal, seconal,
• Antiseptics: - Chemicals which kill or prevent the growth of microorganisms without harming living tissues. Antiseptics: They can be applied to wounds, cuts, ulcers and diseased

skin surfaces. Tincture of iodine (2-3% iodine in alcohol-water solution) and iodoform act as antiseptic. Eg: - Dettol, iodoform  savlon, , mercurochrome, boric acid, potassium permanganate and 0.2% solutio'n of phenol etc.

Antipyretics: They are drugs, which bring down the body temperature in high fever. Examples are aspirin, phenacetin ,

paracetamol (4-acetamidophenol), analgin , novalgin.

·         Disinfectant: - Kill or prevent the growth of microorganism but not safe for living tissues. These are applied to inanimate object such as floor, instruments, walls, eg. 2% solution ofphenol acts as disinfectant, 0.2 to 0.4 parts per million is used for disinfecting drinkingwater and low concentration of S0₂ is used for sterilising squashes for preservation.Eg : 0.2-0.4 ppm chlorine; 1 % soln. of phenol

·         Antimicrobial: - Chemicals used to control microbial diseases Eg. Tetracycline, Penicillin

·         Pathogen: -Any organism that causes disease is called pathogen

·         Antifertility drug: -Chemical substances used for birth control Eg. Norethindrone, Ethynylestradiol , Mifepristone.

·         Antihistamines: - Anti-allergic drugs, they are used to treat allergy like skin rashes, conjunctivitis (eye disease), these drugs relieve sneezing, nasal discharge and soaring of eyes, nose and throat. Since the allergic reactions are caused due to liberation of histamine in the body that is why these drugs are called antihistamines.

Eg. Diphenylhydramine, chloropheneramine & Promethazine.

·         Antibiotics: - Chemicals produced by microorganisms to inhibit the growth for even destroy microorganisms Eg. Penicillin, Tetracycline etc.

·         Narrow Spectrum Antibiotics: -Effective against one microorganism

·         Broad Spectrum Antibiotics: -Effective against several types of micro-organisms

Eg. - Chlormaphenicol, Tetracycline.

·         Sulpha-drugs: - Sulphur containing chemicals used in the place of antibiotics Eg. - Sulphadiazine

·         Anta-acids: - Substances which remove the excess acid and raise the pH to appropriate level

in stomach are called antacids. Eg: Milk of magnesia [Mg(OH)₂], magnesium carbonate, magnesium trisilicate, aluminium hydroxide gel, sodium bicarbonate and aluminium phosphate, Omperazole, Lansoprazole are recent antacids.

·         Aspirin: Aspirin is the common name for 2-acetoxy benzoic acid and is most widely used

As pain reliever. Its name is acetyl salicylic acid.

·         Narcotics: They produce sleep and unconsciousness. They are also used as analgesics.They cause addiction (habit-forming). Typical examples of narcotics are morphine, codeine and heroin. They are not commonly used in these days due to their habit-forming effect.

·         Hypnotics: These drugs which produce sleep are called hypnotics e.g., veronal, amytal,

  luminal and seconal are called barbiturates and are hypnotics.

Designing a Drug.

There are two factors which  are kept in mind while designing a drug.

(i)             Drug target                   (ii)Drug metabolism.

(i) Drug target. Drugs usually interact with carbohydrates, lipids, proteins and nucleic acids. These molecules are called targets. The choice of target for a drug is important to obtain desired curative effect (ability to cure disease).

(ii)            Drug metabolism. Drug should reach its target without undergoing metabolism. It

should easily be excreted without cause harm to our body.

Chemicals used in food:

·         Antioxidants: - Retard the action of oxygen on the food and help in preservation

      Eg. Butylated hydroxy toluene (BHT)

·         Artificial sweeteners: - The artificial sweeteners are another type of food additives and are synthesized in the lab, e.g.,Saccharin is marketed as soluble or calcium salt. It is 300 times sweet than cane sugar. It is Lifesaver for diabetic patients and is of great value to people who need to control intake of Calories.

Aspartame (as a sugar substitute to cold foods and soft drinks, Alitame, Sucralose

·         Preservatives: - Chemicals used to delay undesirable changes occurring in flavour colour, texture and appetitic appeal during storage are called preservatives. They delay these

changes and prevent spoilage of food due to microbial growth. The most common preservatives are sodium benzoate, C6H5COONa, Salts of propanoic acid, Sorbic acid

·         Edible colours: - Used to colour the foodstuffs They are used to dye orange

peels so that oranges retain their colour. Colour is also added to fruit juices. Food colours do not have any nutritional value. Tetrazine, a widely used dye is harmful Natural dyes likecarotene are safe food edible colours. Eg. Carotene

Detergents:

They are sodium or potassium salts of sulphonic acids, e.g., sodium alkyl benzene sulphonate.

·         Classification:

·         Anionic- Long chain alcohols are used in the manufacture of some the synthetic anionic detergents. The long chain alcohols are treated with concentrated sulphuric acid to form

alkyl hydrogen sulphate of high molecular mass and finally alkyl sulphate are neutralised with alkali to form salts-alkyl benzene sulphonates

• Cationic: These are mostly acetates or chlorides of quaternary ammonium salts. They are more expensive, therefore used to limited extent. These detergents possess germicidal properties and are used extensively as germicides. Eg  cetyltrimethyl ammonium chloride
• Non-ionic: - Some of the detergents are non-ionic, like the esters of high molecular mass formed by reactions between polyethylene glycol and stearic acid

·         Advantages of detergents:

(i) They work well even with hard water.

(ii) They are more effective than soaps.

(iii) They can work well even with acidic water.

(iv) They can work well with woollen garments.

Soaps:

Soaps used for cleaning purpose are sodium or potassium salts of long chain fatty acids

e.g., stearic, oleic and palmitic acids. Soaps containing sodium salts are formed by heating fat (i.e  glyceryl  ester of fatty acid) with aqueous sodium hydroxide solution. This  reaction is called saponification. The reaction for making soap from glyceryl ester of stearic acid with sodium hydroxide is given below:

Q 16.1: Sleeping pills are recommended by doctors to the patients suffering from sleeplessness but it is not advisable to take its doses without consultation with the doctor, Why?

Most drugs when taken in doses higher than recommended may cause harmful effects and sometimes, may even lead to death. Hence, a doctor should always be consulted before taking any medicine.

Q 16.2:Why do we require artificial sweetening agents?
                A large number of people are suffering from diseases such as   diabetes and obesity. These people cannot take normal sugar   i.e., sucrose as it is harmful for them. Therefore, artificial
 sweetening  agents that do not add to the calorie intake of a
  person are required.  Saccharin, aspartame, and alitame are a
 few  examples of artificial   sweeteners.

Q 16.3Write the chemical equation for preparing sodium soap  
                from glyceryl oleate and glyceryl palmitate. Structural  formulae of these compounds are given below.(i)          
                     

 

(ii)

Answer  (i)

         

           





Q 16.4:Following type of nom-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) present in the molecule.

Answer

Q 16.  While antacids and antiallergic drugs interfere with the function of histamines, why do these not interfere with the function of each other?

Answer  Specific drugs affect particular receptors. Antacids and anti-allergic drugs work on different receptors..

Q 16.6:Why are cimetidine and ranitidine better antacids than sodium hydrogen carbonate or magnesium or aluminium hydroxide?

Answer  Cimetidine and rantidine are better antacids as they control the root cause of acidity. These drugs prevent the interaction of histamine with the receptors present in the stomach walls. Consequently, there is a decrease in the amount of acid released by the stomach.
Antacids such as sodium hydrogen carbonate, magnesium hydroxide, and aluminium hydroxide work by neutralising the excess hydrochloric acid present in the stomach. However, the root cause for the release of excess acid remains untreated.

Q 16.7:Why is use of aspartame limited to cold foods and drinks?

Answer Aspartame becomes unstable at cooking temperature. This is  the reason why its use is limited to cold foods and drinks.

Q 16.8: Name a sweetening agent used in the preparation of sweets for a diabetic patient.

Answer Artificial sweetening agents such as saccharin, alitame, and aspartame can be used in preparing sweets for diabetic patients.

Q 16.9:What problem arises in using alitame as artificial sweetener?

Answer Alitame is a high potency sweetener. It is difficult to control the sweetness of food while using alitame as an artificial sweetener.

HOTS 

1 MARK QS

Q. 1.        Give an example of a chemical substance which can act both as an antiseptic and disinfectant.

Ans.        Phenol.

Q. 2.        What is the chemical name of antiseptic chloroxylenol ?

Ans.        4-Chloro-3, 5-dimethyl phenol.

Q. 3.        Which alkaloid is used to control hypertension ?

Ans.        Reserpine.

Q. 4.        Which alkaloid is used to treat malaria ?

Ans.        Quinine.

Q. 5.        Identify the following :

Ans.        Paracetamol.

Q. 6.        What are the main constituents of dettol?\

Ans         The main constituents of dettol are chloroxylenol and α-terpineol.

Q. 7.        Which artificial sweetner has the lowest sweetness value ?

Ans.        Aspartame.

Q. 8.        Which artificial sweetner has the highest sweetness value ?

Ans.        Alitame.

Q. 9.        What kind of a drug is Chlorpheniramine maleate ?

Ans.        Anti histamine drug.

Q. 10.     What is the chemical name of aspirin ?

Ans.        2-Acetoxy benzoic acid.

Q. 11.     Name the antibacterial present in toothpaste.

Ans.        Triclosan.

Q12 Distinguish between a narrow spectrum and broad spectrum antibiotic.

Ans.        A narrow spectrum antibiotic works against a limited range of microbes whereas a broad spectrum antibiotic works against a large variety of microbes.

Q. 13.     Which antibiotic contains NO2 group attached to aromatic nucleus in its structure ?

Ans.        Chloramphenicol.

Q. 14.     What is the use of barbituric acid ?

Ans.        Tranquilizer.

Q.            Name one analgesic drug which is also used to prevent heart attacks.

Ans.        Aspirin.

Q. 16. Give an example of a drug that is antipyretic as well as analgesic.

Ans.        Paracetamol.

Ans.        It is a detergent.

Q. 17.     When a mixture of salicylic acid, acetic anhydride and acetic acid is refluxed, what is the product obtained and what is its use in everyday life ?

Ans.        Aspirin used as analgesic.

Q. 18.     Out of morphine, N-Acetyl-para-aminophenol, Diazepam and tetrahydrocatenol, which can be used as analgesic without causing addiction ?

Ans.        N-Acetyl-para-aminophenol.

Q. 19.     Name a sugar substitute which is 160 times as sweet as surcrose.

Ans.        Aspartame.

Q.20.      What is Salvarson ? To which class of drugs does it belong ? For what distance is it used ?

Ans.        Antimicrobial agent.

                Used for the treatment of STD called Syphilis

Q 21  :What are food preservatives?

Answer Food preservatives are chemicals that prevent food from spoilage due to microbial growth. Table salt, sodium benzoate (C₆H₃COONa),

Q 22    Why is bithional added to soap ?

Ans.        Acts as an antiseptic and reduces the odours produced by bacterial decomposition of organic matter on the skin. CHEMISTRY IN EVERY DAY LIFE

 

IMPORTANT POINTS TO REMEMBER
By   Mukesh  Sharma

Chemicals in medicines:

·         Drugs: Chemical substances used for treatment of diseases and for reducing pain are called drugs or medicines.

·         Chemotherapy: Chemotherapy is the science in which chemicals are used in treatment of diseases due to bacterial invasion. These chemicals destroy the microorganisms without

            Affecting, to any material extent, the tissues (of the host).

·         Classification of Drugs.

Drugs can be classified in several ways.

Based on pharmacological effect.

Drugs ill classified on the basis of their physicological effect on our body e.g., antipyretic drugs reduce temperature of several body whereas antiseptic drugs prevent the growth of micro-organism

Based on a particular biochemical process:

Some drugs affect biochemical processes, e,g., antihistamines drugs supress the action nl histamine which causes inflammation in iliI body.

Based on chemical nature.

Some drugs have effect on the body based on their structural features, e.g., sulpha drugs can supress illness multiplication of micro-organisms like bacteria due to their structure, therefore, they are used as antibacterial.

Based on molecular targets.

They are based on molecular targets like enzymes, receptor of cell, macromolecules like carbohydrate!, proteins, lipids, nucleic acids.

Based on therapeutic action:

• Analgesics: Drugs used for relieving pain e.g.:- Aspirin, codeine, heroin etc.
• Tranquilizers: - Class of chemical compounds used for treatment of stress and mental diseases. Eg: - Luminal, seconal,
• Antiseptics: - Chemicals which kill or prevent the growth of microorganisms without harming living tissues. Antiseptics: They can be applied to wounds, cuts, ulcers and diseased

skin surfaces. Tincture of iodine (2-3% iodine in alcohol-water solution) and iodoform act as antiseptic. Eg: - Dettol, iodoform  savlon, , mercurochrome, boric acid, potassium permanganate and 0.2% solutio'n of phenol etc.

Antipyretics: They are drugs, which bring down the body temperature in high fever. Examples are aspirin, phenacetin ,

paracetamol (4-acetamidophenol), analgin , novalgin.

·         Disinfectant: - Kill or prevent the growth of microorganism but not safe for living tissues. These are applied to inanimate object such as floor, instruments, walls, eg. 2% solution ofphenol acts as disinfectant, 0.2 to 0.4 parts per million is used for disinfecting drinkingwater and low concentration of S0₂ is used for sterilising squashes for preservation.Eg : 0.2-0.4 ppm chlorine; 1 % soln. of phenol

·         Antimicrobial: - Chemicals used to control microbial diseases Eg. Tetracycline, Penicillin

·         Pathogen: -Any organism that causes disease is called pathogen

·         Antifertility drug: -Chemical substances used for birth control Eg. Norethindrone, Ethynylestradiol , Mifepristone.

·         Antihistamines: - Anti-allergic drugs, they are used to treat allergy like skin rashes, conjunctivitis (eye disease), these drugs relieve sneezing, nasal discharge and soaring of eyes, nose and throat. Since the allergic reactions are caused due to liberation of histamine in the body that is why these drugs are called antihistamines.

Eg. Diphenylhydramine, chloropheneramine & Promethazine.

·         Antibiotics: - Chemicals produced by microorganisms to inhibit the growth for even destroy microorganisms Eg. Penicillin, Tetracycline etc.

·         Narrow Spectrum Antibiotics: -Effective against one microorganism

·         Broad Spectrum Antibiotics: -Effective against several types of micro-organisms

Eg. - Chlormaphenicol, Tetracycline.

·         Sulpha-drugs: - Sulphur containing chemicals used in the place of antibiotics Eg. - Sulphadiazine

·         Anta-acids: - Substances which remove the excess acid and raise the pH to appropriate level

in stomach are called antacids. Eg: Milk of magnesia [Mg(OH)₂], magnesium carbonate, magnesium trisilicate, aluminium hydroxide gel, sodium bicarbonate and aluminium phosphate, Omperazole, Lansoprazole are recent antacids.

·         Aspirin: Aspirin is the common name for 2-acetoxy benzoic acid and is most widely used

As pain reliever. Its name is acetyl salicylic acid.

·         Narcotics: They produce sleep and unconsciousness. They are also used as analgesics.They cause addiction (habit-forming). Typical examples of narcotics are morphine, codeine and heroin. They are not commonly used in these days due to their habit-forming effect.

·         Hypnotics: These drugs which produce sleep are called hypnotics e.g., veronal, amytal,

  luminal and seconal are called barbiturates and are hypnotics.

Designing a Drug.

There are two factors which  are kept in mind while designing a drug.

(i)             Drug target                   (ii)Drug metabolism.

(i) Drug target. Drugs usually interact with carbohydrates, lipids, proteins and nucleic acids. These molecules are called targets. The choice of target for a drug is important to obtain desired curative effect (ability to cure disease).

(ii)            Drug metabolism. Drug should reach its target without undergoing metabolism. It

should easily be excreted without cause harm to our body.

Chemicals used in food:

·         Antioxidants: - Retard the action of oxygen on the food and help in preservation

      Eg. Butylated hydroxy toluene (BHT)

·         Artificial sweeteners: - The artificial sweeteners are another type of food additives and are synthesized in the lab, e.g.,Saccharin is marketed as soluble or calcium salt. It is 300 times sweet than cane sugar. It is Lifesaver for diabetic patients and is of great value to people who need to control intake of Calories.

Aspartame (as a sugar substitute to cold foods and soft drinks, Alitame, Sucralose

·         Preservatives: - Chemicals used to delay undesirable changes occurring in flavour colour, texture and appetitic appeal during storage are called preservatives. They delay these

changes and prevent spoilage of food due to microbial growth. The most common preservatives are sodium benzoate, C6H5COONa, Salts of propanoic acid, Sorbic acid

·         Edible colours: - Used to colour the foodstuffs They are used to dye orange

peels so that oranges retain their colour. Colour is also added to fruit juices. Food colours do not have any nutritional value. Tetrazine, a widely used dye is harmful Natural dyes likecarotene are safe food edible colours. Eg. Carotene

Detergents:

They are sodium or potassium salts of sulphonic acids, e.g., sodium alkyl benzene sulphonate.

·         Classification:

·         Anionic- Long chain alcohols are used in the manufacture of some the synthetic anionic detergents. The long chain alcohols are treated with concentrated sulphuric acid to form

alkyl hydrogen sulphate of high molecular mass and finally alkyl sulphate are neutralised with alkali to form salts-alkyl benzene sulphonates

• Cationic: These are mostly acetates or chlorides of quaternary ammonium salts. They are more expensive, therefore used to limited extent. These detergents possess germicidal properties and are used extensively as germicides. Eg  cetyltrimethyl ammonium chloride
• Non-ionic: - Some of the detergents are non-ionic, like the esters of high molecular mass formed by reactions between polyethylene glycol and stearic acid

·         Advantages of detergents:

(i) They work well even with hard water.

(ii) They are more effective than soaps.

(iii) They can work well even with acidic water.

(iv) They can work well with woollen garments.

Soaps:

Soaps used for cleaning purpose are sodium or potassium salts of long chain fatty acids

e.g., stearic, oleic and palmitic acids. Soaps containing sodium salts are formed by heating fat (i.e  glyceryl  ester of fatty acid) with aqueous sodium hydroxide solution. This  reaction is called saponification. The reaction for making soap from glyceryl ester of stearic acid with sodium hydroxide is given below:

Q 16.1: Sleeping pills are recommended by doctors to the patients suffering from sleeplessness but it is not advisable to take its doses without consultation with the doctor, Why?

Most drugs when taken in doses higher than recommended may cause harmful effects and sometimes, may even lead to death. Hence, a doctor should always be consulted before taking any medicine.

Q 16.2:Why do we require artificial sweetening agents?
                A large number of people are suffering from diseases such as   diabetes and obesity. These people cannot take normal sugar   i.e., sucrose as it is harmful for them. Therefore, artificial
 sweetening  agents that do not add to the calorie intake of a
  person are required.  Saccharin, aspartame, and alitame are a
 few  examples of artificial   sweeteners.

Q 16.3Write the chemical equation for preparing sodium soap  
                from glyceryl oleate and glyceryl palmitate. Structural  formulae of these compounds are given below.(i)          
                    

(ii)

Answer  (i)

         

Q 16.4:Following type of nom-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) present in the molecule.

Answer

Q 16.  While antacids and antiallergic drugs interfere with the function of histamines, why do these not interfere with the function of each other?

Answer  Specific drugs affect particular receptors. Antacids and anti-allergic drugs work on different receptors..

Q 16.6:Why are cimetidine and ranitidine better antacids than sodium hydrogen carbonate or magnesium or aluminium hydroxide?

Answer  Cimetidine and rantidine are better antacids as they control the root cause of acidity. These drugs prevent the interaction of histamine with the receptors present in the stomach walls. Consequently, there is a decrease in the amount of acid released by the stomach.
Antacids such as sodium hydrogen carbonate, magnesium hydroxide, and aluminium hydroxide work by neutralising the excess hydrochloric acid present in the stomach. However, the root cause for the release of excess acid remains untreated.

Q 16.7:Why is use of aspartame limited to cold foods and drinks?

Answer Aspartame becomes unstable at cooking temperature. This is  the reason why its use is limited to cold foods and drinks.

Q 16.8: Name a sweetening agent used in the preparation of sweets for a diabetic patient.

Answer Artificial sweetening agents such as saccharin, alitame, and aspartame can be used in preparing sweets for diabetic patients.

Q 16.9:What problem arises in using alitame as artificial sweetener?

Answer Alitame is a high potency sweetener. It is difficult to control the sweetness of food while using alitame as an artificial sweetener.

HOTS 

1 MARK QS

Q. 1.        Give an example of a chemical substance which can act both as an antiseptic and disinfectant.

Ans.        Phenol.

Q. 2.        What is the chemical name of antiseptic chloroxylenol ?

Ans.        4-Chloro-3, 5-dimethyl phenol.

Q. 3.        Which alkaloid is used to control hypertension ?

Ans.        Reserpine.

Q. 4.        Which alkaloid is used to treat malaria ?

Ans.        Quinine.

Q. 5.        Identify the following :

Ans.        Paracetamol.

Q. 6.        What are the main constituents of dettol?\

Ans         The main constituents of dettol are chloroxylenol and α-terpineol.

Q. 7.        Which artificial sweetner has the lowest sweetness value ?

Ans.        Aspartame.

Q. 8.        Which artificial sweetner has the highest sweetness value ?

Ans.        Alitame.

Q. 9.        What kind of a drug is Chlorpheniramine maleate ?

Ans.        Anti histamine drug.

Q. 10.     What is the chemical name of aspirin ?

Ans.        2-Acetoxy benzoic acid.

Q. 11.     Name the antibacterial present in toothpaste.

Ans.        Triclosan.

Q12 Distinguish between a narrow spectrum and broad spectrum antibiotic.

Ans.        A narrow spectrum antibiotic works against a limited range of microbes whereas a broad spectrum antibiotic works against a large variety of microbes.

Q. 13.     Which antibiotic contains NO2 group attached to aromatic nucleus in its structure ?

Ans.        Chloramphenicol.

Q. 14.     What is the use of barbituric acid ?

Ans.        Tranquilizer.

Q.            Name one analgesic drug which is also used to prevent heart attacks.

Ans.        Aspirin.

Q. 16. Give an example of a drug that is antipyretic as well as analgesic.

Ans.        Paracetamol.

Ans.        It is a detergent.

Q. 17.     When a mixture of salicylic acid, acetic anhydride and acetic acid is refluxed, what is the product obtained and what is its use in everyday life ?

Ans.        Aspirin used as analgesic.

Q. 18.     Out of morphine, N-Acetyl-para-aminophenol, Diazepam and tetrahydrocatenol, which can be used as analgesic without causing addiction ?

Ans.        N-Acetyl-para-aminophenol.

Q. 19.     Name a sugar substitute which is 160 times as sweet as surcrose.

Ans.        Aspartame.

Q.20.      What is Salvarson ? To which class of drugs does it belong ? For what distance is it used ?

Ans.        Antimicrobial agent.

                Used for the treatment of STD called Syphilis

Q 21  :What are food preservatives?

Answer Food preservatives are chemicals that prevent food from spoilage due to microbial growth. Table salt, sodium benzoate (C₆H₃COONa),

Q 22    Why is bithional added to soap ?

Ans.        Acts as an antiseptic and reduces the odours produced by bacterial decomposition of organic matter on the skin.