Bihar Board Class 12 Chemistry Solutions Chapter 16 Chemistry in Everyday Life
BSEB Bihar Board Class 12 Chemistry Solutions Chapter 16 Chemistry in Everyday Life
Bihar Board Class 12 Chemistry Chemistry in Everyday Life Intext Questions and Answers
Question 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 doctor. Why?
Answer:
Most of the drugs taken in higher doses than recommended may cause harmful effect and act as poison. Excess of dosage of sleeping pills may prove fatal. Therefore, a doctor must always be consulted for appropriate dose before taking medicine.
Question 2.
With reference to which classification has the statement, “ranitidine is an antacid.” been given.
Answer:
It belongs to antacid group of medicines to control acidity. This statement refers to the classification according to pharmacological effect of the drug as it counteracts the effect of excess of acid in the stomach.
Question 3.
Why do we require artificial sweetening agents?
Answer:
Natural sweeteners like glucose, sucrose etc. add to calorie intake and therefore many people prefer to use artificial sweeteners. They are of great value to diabetic persons and people who are calorie-conscious. They are excreted from the body in the urine unchanged.
Question 4.
Write the chemical equation for preparing sodium soap from glyceryl oleate and glyceryl palmitate. Structural formulae of these compounds are given below.
(i) (C15H31COO)3 C3H5 – Glyceryl palmitate
(ii) (C17H33COO)3 C3H5 – Glyceryl oleate
Answer:
These glycerides on hydrolysis with NaOH (called Saponification) give soaps.
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) present in the molecule.
Bihar Board Class 12 Chemistry Chemistry in Everyday Life Text Book Questions and Answers
Question 1.
Why do we need to classify drugs in different ways?
Answer:
Drugs are classified according to their effects on different elements of the human body. Drugs classification is useful for doctors. For example, analgesics have painkilling effect, whereas antiseptics kill or arrest the growth of microorganisms.
Question 2.
Explain the term, target molecules or drug targets as used in medicinal chemistry.
Answer:
Target molecules or drug targets-Drugs usually interact with biological macromolecules such as carbohydrates, lipids proteins and nucleic acids. These biological molecules are called targets. The correct choice of the molecular target for a drug is important to obtain its desired therapeutic effect.
Question 3.
Name the macromolecules that are chosen as drug targets.
Answer:
Macromolecules that are chosen as drug targets include carbohydrates, lipids, proteins and nucleic acids.
Question 4.
Why should not medicines be taken without consulting doctors?
Answer:
Medicines should always be taken at the advice of the doctors. Medicines affect human metabolism and provide cure from different ciilments of the body. A medicine wrongly taken without the consultation of a doctor may not be effective or may have serious side effects. In larger doses, they may have a poisonous effect.
Question 5.
Define the term Chemotherapy.
Answer:
Use of chemicals in prescribed doses for therapeutical effect is called Chemotherapy.
Question 6.
Which forces are involved in holding the drugs, to the active site of enzymes?
Answer:
Active sites of enzymes hold the drug through a variety of interactions such as ionic bonding, hydrogen bonding, van der waals interactions or dipole-dipole interactions.
Question 7.
While antacids and antiallergic drugs interfere with the function of histamines, why do these not interfere with the function of each other.
Answer:
Both antacids and antiallergic drugs interfere with the function of histamine. Antacid like Cimetidine was designed to prevent the interaction of histamine with the receptors present in the stomach wall [this resulted in release of lesser amount of acid.] Antacid and antiallergic drugs work on different receptors.
Question 8.
Low level of noradrenaline is the cause of depression. What type of drugs are needed to cure this problem? Name two drugs.
Answer:
Noradrenaline is one of the neurotransmitters that plays role in mood changes. If its level is low, the signal-sending activity becomes low and the person suffers from depression. In such a situation, antidepressant drugs are required. These drugs inhibit the enzymes which catalyse the degradation of noradrenaline. If the enzyme is inhibited this important neurotransmitter is slowly metabolised and can activate its receptor for longer periods of time thus counteracting the effect of depression. Iproniazid and phenelzine are two such drugs.
Question 9.
What is instant by the term ‘broad-spectrum antibiotics? Explain.
Answer:
The full range of microorganisms attacked by an antibiotic is called its spectrum. Broad-spectrum antibiotics are medicines effective against several different types of harmful microorganisms, e.g., tetracycline, chloramphenicol and a mixture of potent antibiotics.
Question 10.
How do antiseptics differ from disinfectants? Give an example of each.
Answer:
Antiseptics and disinfectants are the 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. Examples are furacine, soframicine. Disinfectants, on the other hand, are applied to inanimate objects such as floors, drainage system, instruments etc. Chlorine in the concentration of 0.2 to 0.4 ppm and SO2 in very small concentration are disinfectants.
Question 11.
Why are cinetidine and ranitidine better antacides than sodium bicarbonate or magnesium or aluminium hydroxide?
Answer:
Excessive sodium bicarbonate or magnesium or aluminium hydroxide can make the stomach alkaline and trigger the production of even more acid. It was discovered that histamine stimulates the secretion of pepsin and hydrochloric acid. The drugs cinetidine and rontidine were designed to prevent the interaction of histamine with the receptors present in the stomach wall. This resulted in release of lesser amount of acid.
Question 12.
Name a substance which can be used as an antiseptic as well as disinfectant.
Answer:
0.2 per cent solution of phenol is an antiseptic while its one per cent solution is disinfectant.
Question 13.
What are main constituents of Dettol? –
Answer:
Dettol is a mixture of chloroxylenol and terpineol in a suitable solvent.
Question 14.
What is tincture of iodine? What is its use?
Answer:
It is 2-3 % solution of iodine in alcohol and water. It is a powerful antiseptic.
Question 15.
What are food preservatives?
Answer:
Food preservatives prevent spoilage of food due to microbial growth. Table salt, sugar and vegetable oils are class I preservatives. The most common preservative of class II is sodium benzoate [C6H5CO0Na]. It can be safely used in small quantities which is metabolised in body.
Question 16.
Why is use of aspartame limited to cold foods and fruits?
Answer:
The use of aspartame as an artificial sweeter is limited to cold foods and cold drinks because it is unstable to heat and decomposes at cooking temperature.
Question 17.
What are artificial sweetening agents? Give two examples.
Answer:
Sucrose, glucose etc. are natural sugars. They add to calorie intake. To cut down on the intake of calories many people use artificial sweeteners such as saccharine (ortho-Sulpho-benzamide) which is 550 times as sweet as sugar (mass to mass) with negligible calories. It is excreted from the body in urine unchanged. It. is entirely inert and harmless when taken. It is of great value to diabetic persons and people who need to control intake of calories. Other example of artificial sweeteners are aspartame, sucrose, all tame.
Question 18.
Name the sweetening agent used in the preparation of sweet for a diabetic patient.
Answer:
Sucrolose which is trichloro derivative of sucrose and has appearance and tastes like sugar is stable at cooking temperature. It is a zero-calorie sweetener.
Question 19.
What problem arises in using alitame as artificial sweetener?
Answer:
Alitame is high potency sweetener (Mass per mass it is 2000 times sweeter than can sugar). The control of sweetness of food is difficult while using it.
Question 20.
How are synthetic detergents better than soap?
Answer:
Soaps when used in hard water form curdy precipitate that separates as scum. These insoluble soaps are useless as cleansing agent. Synthetic detergents, on the other hand, can be used in any sort of water because they form foam even in water containing mineral compounds. Some of them can give foam even in ice-cold water.
Question 21.
Explain the following terms with suitable examples.
(a) cationic detergents, (b) anionic detergents and (c) neutral detergents.
Answer:
(a) Cationic detergents-They are acetates, chlorides or bromides of quaternary ammonium salts. Cationic part possesses a long hydrocarbon chain and a positive charge. Hence these are called cationic detergents. Example is cetylmethyl ammonium bromide whose structure is given.
(b) Anionic detergents-Anionic detergents are sodium salts of sulphonated long-chain alcohols. Alkyl hydrogen sulphonates formed by treating long-chain alcohols with concentrated sulphuric acid are neutralised with alkali to form anionic detergents. Sodium lauryl sulphonate CH3 (CH2)10 CH2O , SO3– Na+ is an example. In anionic detergents, anionic part of the molecule is involved in die cleansing action. They are also used in toothpastes.
(c) Neutral detergents-Stearic add reacts with polyethene glycol to form non-ionic /neutral detergents.
Liquid dishwashing detergents are non-ionic type.
Question 22.
What are biodegradable and non-biodegradable detergents? Give one example of each.
Answer:
Detergents having straight hydrocarbon chains are easily degraded (or decomposed) by microorganisms and hence are called biodegradable detergents while detergents containing branched hydrocarbon chains are not easily degraded by the microorganisms and hence are called non-biodegradable detergents.
Sodium alkyl sulphates like sodium lauryl sulphate is 100 % biodegradable.
These insoluble soaps are useless as cleansing agent. In fact these are hindrances to good washing because this precipitate adheres on to the fibres of the cloth as gummy mass.
Question 24.
Can you use soaps and synthetic detergents to check the hardness of water?
Answer:
Soaps and detergents can be used to check the hardness of water. Hard water forms curdy white precipitate with Ca2+ and Mg2+ ions present in hard water where as no such precipitates are formed by detergents in hard water.
Question 25.
Explain the cleansing action of soaps.
Answer:
All the soaps and detergents contain two characteristic groups, i.e., a water-soluble (hydrophilic) group and oil-soluble (Lyophilic or lipophilic group). As a result one end of the molecule of a soap or detergent tends to go into oil phase and the other end tends to go into water phase with the net result that the material (soap or detergent) concentrates at the surface of the solution or interace.
The dirt is generally held to a dirty surface by a thin film of an oil or grease. When it is treated with soap solution, the non-polar hydrocarbon chain of soap or detergent dissolves in oil or grease and the carboxylate part of the soap or the sulphonate group of the detergent is held by surrounding water (in fig. below). This lowers the surface tension between water and grease. As a result, a stable emulsion of oil in water is formed. When the surface or the cloth is mechanically scrubbed the loosened dirt particles are absorbed by colloidal soap particles and ultimately washed away by water.
Question 26.
If water contains dissolved calcium bicarbonate, out of soaps and synthetic detergents which one will you use for cleansing clothes?
Answer:
Synthetic detergents.
Question 27.
Label the hydrophilic and hydrophobic parts in the following compounds.
(c) CH3 (CH2)16 COO (CH2CH2O)n CH2CH2OH
Answer: