RBSE Class 12 Chemistry Notes Chapter 16 Chemistry in Everyday Life

These comprehensive RBSE Class 12 Chemistry Notes Chapter 16 Chemistry in Everyday Life will give a brief overview of all the concepts.

RBSE Class 12 Chemistry Chapter 16 Notes Chemistry in Everyday Life

→ A medicine is a chemical substance which cures the disease, is safe to use, has negligible toxicity and does not cause addiction.

→ A drug is a chemical substance which cures the disease but its habit causes addiction and has serious side effects.

→ The branch of chemistry which deals with the treatment of diseases using suitable chemicals is known as Chemotherapy.

→ Drugs usually interact with biomolecules such as carbohydrates, proteins, lipids and nucleic acids.

→ Enzymes are biocatalysts. The first function of an enzyme is to had the substrate molecule for a chemical reaction. The second function of an enzyme is to provide functional groups that will attack the substrate and carry out chemical reaction.

→ In the body, the message between two neurons or that between neurons to muscles is communicated through certain chemicals called chemical messengers.

 

→ Chemical messengers are of two types: hormones and neurotransmitters.

→ Hormones are the group of biomolecules which are produced in the endocrine (ductless) glands and are transferred to the different body parts of the blood stream and control various metabolic processes.

→ Neurons transfer message through neurotransmitters.

→ Acetylcholine, serotonin and dopamine are the important neurotransmitters.

→ Antagonists are those drugs that bind to the receptor site and inhibit its normal functioning.

→ Agonists are the drugs that mimic the natural messengers and take positions on the receptors.

→ Antacids: Substances which neutralize the excess hydrochloric acid and raise the pH value to an appropriate level in stomach are called antacids. For example: sodium bicarbonate, magnesium hydroxide, magnesium carbonate, aluminium hydroxide gel, etc.

→ Since histamines stimulate the secretion of pepsin and HQ, therefore some antihistamines which prevent the inter-action of histamines with the receptors present in the stomach wall are used as antacids. For example, cimetidine (tegamet) or rantidine (zintac). Omepurazole and lansoprazole have been also used as antacids.

→ Antihistamines: The drugs which interfere with the natural action of histamine by competing with histamine for binding site of receptor where histamine exerts its effect are known as antihistamines or anti allergic drugs.
For example : Bromopheniramine (Dimetapp), Terfenadiene (seldan), Diphenylhydramine, promethazine, chlorpheniramine, etc.

→ Neurologically active durgs: Tranquilizers and analgesics are neurologically active drugs. They affect the message transfer mechanism from neurons to receptors.
(a) Tranquilizers: Tranquilizers are a class of chemical compounds used for the treatment of stress and mild or even severe mental diseases. These relive anxiety, stress, irritability or excitement by inducing a sense of well being. For example, iproniazid, phenelziene chlordiazepoxide, meprobamate, valium, serotonin, veronal, saconal, luminal, etc.

(b) Analgesics: Neurologically active drugs which reduce or abolish pain without causing impairment of conscious-ness, mental confusion, incoordination or paralysis or some other disturbances of nervous system are known as analgesics. These are of two types:

• Non-narcotic (non-addictive) analgesics: Aspirin, paracetamol, naproxen, ibuprofen, dichlofenac sodium, etc.
• Narcotic (addictive) analgesics: Morphine, heroin, codeine, etc.

→ Antipyretics: Drugs which are used to bring down the body temperature during high fever are known as antipyretics. For example : Aspirin, analgin, phenacetin,, paracetamol, etc.

→ Antimicrobials: Drugs which are used to cure diseases caused by microorganims i.e., bacteria, viruses, fungi etc. are known as antimicrobials. These include antibacterials, antifungal and antiviral agents.

→ Antibiotics: Antibiotics are substances produced completely or partially by chemical synthesis which in low concen-trations inhibit the growth or destroy microorganisms by intervening in their metabolic processes. The first anitbiotic discovered by Alexander Flemming in 1929 from the mould penicillium notatum was penicillin.

→ Antibiotics which kill or inhibit a wide range of gram-positive and gram negative bacteria are said to be broad spectrum antibiotics. For example: chloramphenicol, ofloxacin, etc.

→ Antibiotics which are effective mainly against gram-positive or gram negative bacteria are called narrow spectrum antibiotics. For example: penicillin.

→ Sulpha drugs : A group of drugs which are derivatives of p-amino beznene sulphonamide (sulphanilamide) are known as sulpha drugs. For example : sulphodiazine, sulphapyridine, sulphaguanidine, sulphathiozole, sulphacetamide, etc.

→ Antiseptics: These are the chemical substances which prevent the growth of microorganisms and may even kill them. Antiseptics are applied to living tissues such as wounds, cuts, ulcers and diseased skin surfaces. For example, tincture of iodine, iodoform, boric acid, etc.

→ Disinfectants : Chemical substances which kill microorganisms but are not safe for living tissues are known as disinfectants. These are used only on inanimate objects such as drains, toilets, floors etc. For example: Chlorine, thymol and a solution of cresols.

→ Antifertility drugs: Chemical substances which are used to check pregnancy in women are known as antifertility drugs or birth control pills or oral contraceptives. These are mostly hormonal and are available for the females only. For example, norethindrone, ethynylestradiol, mifepristone, ormeloxifene, etc.

→ Artificial sweeteners: Artificial sweeteners are the chemical compounds which give sweetening effect to the food and enhance its odour and colour also. They do not add to calorie intake. For example: saccharin, aspartame, alitame, sucralose, cylamate, L-glucose, etc. 

→ Food preservatives: Chemical substances which are used to protect food materials against various microorganisms
i. e., bacteria, yeasts, moulds, etc. are known as food preservatives. For example: table salt, sugar, vegetable oil, sodium benzoate, sodium metabisulphite, sorbic acid and its salts, p-hydroxy benzoate, etc.

→ Cleansing agents: Those chemical substances which concentrate at the surface of the solution or interfaces, form surface films, reduce surface tension of the solution and help in removing dirt and dust by emulsification are knows as surface active agents or surfactants or cleansing agents. These are soaps synthetic detergents.

→ Soaps: Soaps are sodium or potassium salts of long chain fatty acids such as lauric acid, palmitic acid, stearic acid, oleic acid and linoleic acid. Soaps are formed by heating fats or oils with aqueous solution or potassium hyroxide solution. This reaction is termed as saponification.

→ Soaps can not be used in hard water and in acidic solutions.

→ Detergents : These are ammonium sulphonates or sulphate salts of long chain hydrocarbons containing 12 - 18 carbon atoms. But the common detergents are the sodium salts of long chain fatty acids. Synthetic detergents are mainly classified into three categories:

• Anionic detergents: Sodium alkyl sulphates and sodium alkylbenzene sulphonates.
• Cationic detergents: Cetyltrimethyl ammonium bromide.
• Non-ionic detergents: Polyethylene glycol stearate.