Chapter:6 General Principles & Process of Isolation of Elements
Important Points :1. The chemical substances in the earth’s crust obtained by mining are called Minerals.
2. Minerals, which act as source for metal, are called Ore. From ore metal can be obtained economically .
3. The unwanted impurities present in ore are called Gangue.
4. The entire process of extraction of metal from its ore is called Metallurgy.
5. Removal of gangue from ore is called Concentration, Dressing or Benefaction of ore.
6. Concentration by Hydraulic washing is based on the difference in gravities of ore and gangue particles.
7. Concentration by Magnetic separation is based on differences in magnetic properties of ore components. If either of ore or gangue is capable of attracted by a magnet field, then such separation is carried out.
8. Concentration by Froth Flotation Process is based on the facts that sulphide ore is wetted by oil & gangue particles are wetted by water.
9. Concentration by Leaching is based on the facts that ore is soluble in some suitable reagent & gangue is insoluble in same reagent. e.g. Bauxite ore contains impurities of silica, iron oxide & TiO2 .The powdered ore is treated with NaOH which dissolve Al & impurities remains insoluble in it. Al2O3 +2NaOH + 3 H2O 2 Na [Al(OH)4].
10. Calcination involves heating of ore in absence of air below melting point of metal. In this process volatile impurities escapes leaving behind metal oxide. Fe2O3.xH2O Fe2O3 +xH2O ZnCO3 ZnO +CO2 CaCO3.MgCO3 CaO + MgO + 2CO2
11. Roasting involves heating of ore in presence of air below melting point of metal in reverberatory furnace. In this process volatile impurities escapes leaving behind metal oxide and metal sulphide converts to metal oxide. 2 ZnS + 3 O2 2ZnO+2SO2 2PbS + 3 O2 2 PbO +2 SO2 2 Cu2S + 3 O2 2Cu2O + 2 SO2
12. Reduction of metal oxide involves heating of metal in presence of suitable reagent Coke or CO2. 13. Reactions taking place at different zones of blast furnace in extraction of iron:-
(i) Zone of reduction:- Temperature range 250o C-700o C 3Fe2O3+CO 2Fe3O4+CO2 Fe3O4+CO 3FeO+ CO2 FeO +CO Fe+ CO2
(ii) Zone of slag formation:- Temperature range 800o C-1000o C CaCO3 CaO+CO2 CaO+SiO2 CaSiO3, P4O10+10C 4P+10CO, SiO2+2C Si+2CO, MnO2+2C Mn+2CO
(iii) Zone of fusion: - Temperature range 1150o C-1350o C CO2 + C 2CO
(iv) Zone of fusion: - Temperature range 1450o C-1950o C C +O2 CO2
14. FLOW SHEET FOR EXTRACTION OF IRON:-
Iron ore(Magnetite Fe3O4)(Haematite Fe2O3) ↓ Concentration is done by Gravity separation followed by magnetic separation ↓ Calcination &Roasting i.e. Ore + Air +Heat→Moisture,CO2,SO2, As2O3 removed And FeO oxidized to Fe2O3 ↓ Smelting of charge i.e. mixture of ore, coke & CaCO3 takes place in long BLAST FURNACE.
Following reaction take place at different zones:- (refer to point 13) ↓ Pig iron is obtained, which is remelted and cooled then cast iron is obtained
15. Pig Iron: - It contains Fe 93-95%, Carbon 2.5-5%, and Impurities 3%.
16. Cast Iron: - It contains Fe 99.5-99.8%, Carbon 0.1-0.2% Impurities 0.3%.
17. Spongy iron: - Iron formed in the zone of reduction of blast furnace is called spongy iron. It contains impurities of C, Mn , Si, etc.
18. FLOW SHEET FOR EXTRACTION OF COPPER:-
Copper Pyrites CuFeS2 ↓ Concentration is done by Froth floatation process Powdered ore + water +pine oil +air→ Sulphide ore in the froth ↓ Roasting is presence of air. following reactions take place:- S+ O2→SO2, 4As+3O2→2As2O3, 2CuFeS2+O2 →Cu2S+2FeS+SO2 ↓ Smelting in small blast furnace of a mixture of Roasted ore, coke, and silica. 2FeS + 3O2 → 2FeO + 2SO2, FeO + SiO2 →FeSiO3(slag) ↓ A mixture of Cu2S, FeS & silica is obtained from blast furnace known as Copper matte ↓ Bessemerisation of copper matte is done in Bessemer converter in presence of air. Following reactions take place:- 2FeS + 3O2→2FeO +2 SO2, FeO + SiO2 →FeSiO3 (slag), 2Cu2S + 3O2 →2Cu2O+2SO2, 2Cu2O+2Cu2S→ 6Cu + SO2 ↓ Melted copper is cooled, and then SO2 is evolved. such copper is known as BLISTER COPPER(98%Cu+2% impurities)
19. FLOW SHEET FOR EXTRACTION OF ALUMINIUM:-
Bauxite Al2O3.2H2O ↓ Concentration of ore is done by leaching .Bauxite is treated with NaOH .Following reaction takes place:- Al2O3 +2NaOH + 3 H2O 2 Na [Al (OH) 4] and impurities of Fe2O3, TiO2 &SiO2 are removed. ↓ Na [Al (OH)4] ,then reacts with CO2 then pure Alumina is obtained. Na [Al(OH)4] + 2CO2 → Al2O3.xH2O + 2NaHCO3 ↓ Electrolytic reduction of pure alumina takes place in iron box (cathode) with cryolite (Na3AlF6) & fluorspar CaF2.Graphide rods act as anode. Following reactions take place:- At cathode:- Al3+ + 3e→ Al, At Anode:- 2O2- →O2 + 4e ↓ By this process 98.8% pure Aluminum is obtained.
20. Vapour phase refining is used for extraction of Nickel (MOND PROCESS) and Zirconium &Titanium (VAN ARKEL PROCESS).
21. Zone refining is used for extraction of Si, Ge, Ga, etc.
22. Chromatography method is based on selective distribution of various constituents of a mixture between two phases, a stationary phase and a moving phase. The stationary phase can be either solid or liquid on solid support.
22. Column chromatography is based on adsorption phenomenon. This method is useful for those elements, which are available in small amounts and the impurities are not much different in chemical properties from the element to be purified.
VERY SHORT ANSWER TYPE QUESTION (1 marks)
Q.1- What is slag? A.1- It is easily fusible material fusible material, which is formed when gangue still present in roasted ore combines with the flux. e.g. CaO (flux) + SiO2 (gangue)→CaSiO3 (slag) Q.2- Which is better reducing agent at 983K, carbon or CO? A.2- CO, (above 983K CO being more stable & does not act as a good reducing agent but carbon does.)
Q.3- At which temperature carbon can be used as a reducing agent for Foe ? A.3- Above 1123K, carbon can reduce FeO to Fe.
Q.4- What is the role of graphite rods in electrometallurgy of aluminium ? A.4- Graphite rods act as anode, are attacked by oxygen to form CO2 and so to be replace time to time.
Q.5- What is the role of cryolite in electrometallurgy of aluminium? A.5- alumina cannot be fused easily because of high melting point. Dissolving of alumina in cryolite furnishes Al3+ ions, which can be electrolyzed easily.
Q.6- What are depressants? A.6- It is possible to separate two sulphide ore by adjusting proportion of oil to water in froth flotation process by using a substance known as depressant. e.g. NaCN is used to separate ZnS and PbS.
Q.7- Copper can be extracted by hydrometallurgy but not Zn. Why? A.7- The E0 of Zn is lower than that of Cu thus Zn can displace Cu2+ ion from its solution. On other hand side to displace Zn from Zn2+ ion, we need a more reactive metal than it.
Q.8- Give name and formula of important ore of iron . A.8- Haematite – Fe2O3, Magnetite –Fe3O4, Iron pyrites FeS2.
Q.9- Give name and formula of important ore of Copper . A.9- Copper pyrites CuFeS2, Malachite CuCO3 . Cu (OH) 2, Cuprite Cu2O.
Q.10- Give name and formula of important ore of Zinc . A.10- Zinc blende - ZnS, Calamine- ZnCO3, Zincite – ZnO .
SHORT ANSWER TYPE QUESTION (2 marks)
Q.1 Describe the method of refining of nickel. A.1- In the Mond Process, Ni is heated in a stream of CO forming a volatile complex, which then decomposes at higher temperature to give Ni. At 330-350K: - Ni + 4CO → Ni (CO) 4 At 450-470K Ni (CO)4 → Ni + 4 CO
Q.2- What is Zone Refining? Explain with example. A.2- Zone refining is a method of obtaining a metal in very pure state. It is based on the principal that impurities are more soluble in molten state of metal than solidified state. In this method, a rod of impure metal is moved slowly over circular heater. The portion of the metal being heated melts & forms the molten zone. As this portion of the rod moves out of heater, it solidified while the impurities pass into molten zone. The process is repeated to obtain ultrapure metal and end of rod containing impure metal cutoff.
Q.3 Write the principal of electro-refining.
A.3- In this method of purification impure metal is made Anode and pure metal is made the cathode. On passing electricity, pure metal is deposited at the cathode while the impurities dissolve dissolve in solution as anode mud. E.g. electro- refining of copper:- At Cathode: - Cu2+ + 2e → Cu At Anode: - Cu → Cu2+ + 2e
Q.4- Write difference between calcinations and roasting . A.4- Refer points no 10 &11.
Q.5- Describe the method of refining of Zirconium and Titanium. A.5- Van Arkel process is used for obtaining ultrapure metal. The impure metal is converted into volatile compound, which then decomposes electrically to get pure metal. At 850K: - Zr impure) + 2 I2 → ZnI4 At 2075K:- ZnI4 → Zr (pure) + 2 I2
Q.6- Out of C & CO, which is better reducing agent for ZnO? A.6- Since free energy of formation of CO from C is lower at temperature above 1120K while that of CO2 from carbon is lower above 1323K than free energy of formation 0f ZnO. However, the free energy of formation of CO2 from CO is always higher than that of ZnO. Hence, C is better reducing agent of ZnO.
Q.7- The value of ∆f G0 for Cr2O3 is -540kJ/mole & that of Al2O3 is -827kJ/mole. Is the reduction of Cr2O3 possible with aluminium? A.7- The desired conversion is 4 Al + 2Cr2O3 → 2Al2O3 + 4Cr It is obtained by addition of following two reactions:- 4Al + 3O2 → 2 Al2O3 ∆f G0 =-827kJ/mole 2Cr2O3 → 4Cr + 3O2 ∆f G0 ==+ 540 kJ/mole Therefore, ∆ G0 for desired reaction is -827+540=-287, as a result reduction is possible.
Q.8:- Why copper matte is put in silica lined converter? A.8:- Copper matte consists of Cu2S and FeS. When blast of air is passed through molten matte in silicalined converter, FeS present in matte is oxidized to FeO, which combines with silica to form slag. (i) 2FeS + 3O2→2FeO +2 SO2, (ii) FeO + SiO2 →FeSiO3 (slag), (III) 2Cu2S + 3O2 →2Cu2O+2SO2, (IV) 2Cu2O+2Cu2S→ 6Cu + SO2
Q.9- What is meant by term chromatography? A.9-Chromato means Colour and graphy means writing because the method was first used for separation of coloured substance. It is based on selective distribution of various constituents of a mixture between two phases, a stationary phase and a moving phase. The stationary phase can be either solid or liquid on solid support.
Q.10-Why is reduction of metal oxide easier if metal formed is in liquid state at temperature of reduction. A.10- The entropy of a substance is higher in liquid state than solid state. In the reduction of metal oxide, the entropy change will be positive if metal formed is in liquid state. Thus, the value of ∆ G0 becomes negative and reduction occurs easily.
SHORT ANSWER TYPE QUESTION (3 marks)
Q.1- Explain the following:- (i) Zinc but not copper is used for recovery of Ag from the complex [Ag(CN)2] - . (ii) Partial roasting of sulphide ore is done in the metallurgy of copper. (iii) Extraction of Cu from pyrites is difficult than that from its oxide ore through reduction. A.1- (i) Zn is more powerful reducing agent in comparison to copper.Zn is also cheaper than Cu. (ii) Partial roasting of sulphide ore forms some oxide. This oxide then reacts with remaining sulphide ore to give copper i.e. self-reduction occurs. 2Cu2S + 3O2 →2Cu2O+2SO2, 2Cu2O+2Cu2S→ 6Cu + SO2 . (iii) Though carbon is good reducing agent for oxide but it is poor reducing agent for sulphides. The reduction of metal sulphide does not have large negative value.
Q.2- Explain the method for obtaining pig iron from magnetite. A.2- Extraction of iron from Magnetite takes place in following steps:- (i) Concentration of ore: - It is done by Gravity separation followed by magnetic separation process. (ii) Calcination: - It involve heating when the volatile matter escapes leaving behind metal oxide. Fe2O3.xH2O→ Fe2O3 + xH2O . (iii) Roasting: - It involves heating of ore in presence of air, thus moisture,CO2,SO2, As2O3 removed And FeO oxidized to Fe2O3. (iv) Smelting of roasted ore: - A mixture of ore, coke & CaCO3 is smelted in long BLAST FURNACE. Following reaction takes place at different temperature zones:- (i) Zone of reduction: - Temperature range 250o C-700o C 3Fe2O3+CO 2Fe3O4+CO2 Fe3O4+CO 3FeO+ CO2 FeO +CO Fe+ CO2 (ii) Zone of slag formation:- Temperature range 800o C-1000o C CaCO3 CaO+CO2 CaO+SiO2 CaSiO3, P4O10+10C 4P+10CO, SiO2+2C Si+2CO, MnO2+2C Mn+2CO (iii) Zone of fusion:- Temperature range 1150o C-1350o C CO2 + C 2CO (iv) Zone of fusion:- Temperature range 1450o C-1950o C C +O2 CO2 Thus, Pig iron is obtained from Blast Furnace.
Q.3- Describe the principles of extraction of copper from its ore . A.3- Refer points no 18. For steps, involve in the extraction.
Q.4- Name the principal ore of aluminium and describe how Al is extracted from its ore. A.4- Important ores -(i) Bauxite Al2O3.xH20 (ii) Corrundum Al2O3. Bauxite is commercially important ore Al. Extraction from Bauxite ore involves the following two stages:- (i) Purification of bauxite to get pure alumina (Al2O3 ) (ii)Electrolysis of pure alumina in molten cryolite Step:-1 Bauxite is treated with NaOH .Following reaction takes place:- Al2O3 +2NaOH + 3 H2O 2 Na [Al(OH)4] and impurities of Fe2O3,TiO2 &SiO2 are removed . Na [Al(OH)4] ,then reacts with CO2 then pure Alumina is obtained. Na [Al(OH)4] + 2CO2 → Al2O3.xH2O + 2NaHCO3 Step:-2 Electrolytic reduction of pure alumina takes place in iron box (cathode) with cryolite (Na3AlF6) & fluorspar CaF2.Graphide rods act as anode. Following reactions take place:- At cathode:‐ Al3+ + 3e→ Al, At Anode:‐ 2O2‐ →O2 + By this process 98.8% pure Aluminum is obtained. Q.5- Describe the principles of extraction of Zinc from zinc blende . A.5- Important ores of Zn:-Zinc blende - ZnS, Calamine- ZnCO3, and Zincite – ZnO. ZnS is commercially important ore of Zn.Various stages involved in the extraction of Zn from ZnS are as following:- (i) Concentration of ore:-It is concentrated by Froth flotation process followed by gravity separation process. (ii) Roasting:- The concentrated ore is roasted in presence of air. Following reactions take place:- 2ZnS + 3O2 → 2ZnO + 2SO2 The mass obtained during roasting is porous and is called porous clinker. (iii) Reduction of ZnO to Zn: - ZnO is made into bricketts with coke and clay and heated ai1163K.Zn formed distills off and is collected by rapid cooling of zinc vapours. ZnO + C → Zn + CO
Unit-16 CHEMISTRY IN EVERYDAY LIFE
POINTS TO BE REMEMBERED1. DRUGS – Drugs are chemical of low molecular masses, which interact with macromolecular targets and produce a biological response.
2. CHEMOTHERAPY- The use of chemicals for therapeutic effect is called chemotherapy.
3. CLASSIFICATION OF DRUGS –
(a) ON THE BASIS OF PHARMACOLOGICAL EFFECT-drugs for a particular type of problem as analgesics-----for pain relieving.
(b) ON THE BASIS OF DRUG ACTION-Action of drug on a particular biochemical process.
(c) ON THE BASIS OF CHEMICAL ACTION-Drugs having similar structure .eg-sulpha drugs.
(d) ON THE BASIS OF MOLECULAR TARGETS- Drugs interacting with biomolecules as lipids, proteins.
4. ENZYMES AS DRUG TARGETS (i) CATALYTIC ACTION OF EN ZYMES- (a) Enzymes have active sites which hold the substrate molecule .it can be attracted by reacting molecules. (b) Substrate is bonded to active sites through hydrogen bonds, ionic bonds, Vander Waal or dipole –dipole interactions. (ii) DRUG- ENZYME INTERACTIONS- (a)Drug complete with natural substrate for their attachments on the active sites of enzymes .They are called competitive inhibitors. (b)Some drugs binds to a different site of the enzyme called allosteric sites which changes the shape of active sites.
5. ANTAGONISTS- The drugs that bind to the receptor site and inhibit its natural function.
6. AGONISTS-Drugs mimic the natural messenger by switching on the receptor.
7. ANTACIDS-These are compounds which neutralize excess acid of stomach.eg-Aluminium hydroxide, Magnesium hydroxide.
8. ANTI HISTAMINES-The drugs which interfare with the natural action of histamines and prevent the allergic reaction. eg- rantidine,tegarnet, avil.
9. TRANQULIZERS-The class of chemical compounds used for the treatment of stress,mild or even severe mental diseases. Eg-idardil, iproniagid, luminal, second equaqnil .
10. ANALGESICS-They reduce pain without causing impairment of consciousness, mental confusion or some other disturbance of the nervous system. Eg - aspirin, seridon , phenacetin.
11. ANTIMICROBIALS-They tend to prevent/destroy or inhibit the pathogenic action of microbes as bacteria ,virus ,fungi etc .They are classified as (i)ANTIBIOTICS-Those are the chemicals substances which are produced by micro-organisms. Eg- Pencillin , ofloxacin . NARROW SPECTRUM ANTI-BIOTICS-These are effective mainly against gram positive or gram negative bacteria. Eg- Penicillin , streptomycin. BROAD SPECTRUM ANTI-BIOTICS-They kill or inhibit a wide range of micro-organisms. eg- chloramphenicol , tetracydine . (ii)ANTISEPTICS OR DISINFECTANT-These are which either kill/inhibit the growth of microorganisms Antiseptics are applied to the living tissuses such as wounds, cuts, ulcers etc. egfuracine,chloroxylenol & terpinol(dettol) .Disinfectant are applied to inanimate objects such as floors , drainage , system. Eg- 0.2% solution of phenol is an antiseptic while 1% solution is an disinfectant.
12. ANTIFERTILITY DRUGS- These is the chemical substances used to control the pregnancy. They are also called oral contraceptives or birth control pills. Eg-Mifepristone, norethindrone.
13. ARTIFICIAL SWEETNING AGENTS-These are the chemical compounds which give sweetening effect to the food without adding calorie. They are good for diabatic people eg- aspartame, saccharin, alitame , sucrolose.
14. FOOD PRESERVATIVES- They prevents spoilage of food to microbial growth.eg-salt, sugar, and sodium benzoate.
15. CLEANSING AGENTS- (i) SOAPS- They is sodium or potassium salts of long chain fatty acids.They are obtained by the soapnification reaction, when fatty acids are heated with aqueous sodium hydroxide. They do not work well in hard water. (iii) TOILETS SOAP-That are prepared by using better grade of fatty acids and excess of alkali needs to be removed .colour & perfumes are added to make them attractive. (iv) MEDICATED SOAPS- Substances of medicinal value are added.eg- Buthional , dettol. Downloaded from WWW.STUDIESTODAY.COM
16. SYNTHETIC DETERGENTS-They are cleaning agents having properties of soaps, but actually contain no soap .They can used in both soft and hard water .They are- (i)ANIONIC DETERGENTS-They are sodium salts of sulphonated long chain alcohols or hydrocarbons.eg-sodium lauryl sulphonate . They are effective in acidic solution. CH3 (CH2) CH2OH → CH3 (CH2)10CH2OSO3H (laurylalchol) →CH3 (CH2)10CH2SO3 - Na+ (Sodium lauryl sulphonate) (ii)CATIONIC DETERGENTS- They are quarternary ammonium salts of amines with acetates , chlorides, or bromides.They are expensive used tolimited extent.eg- cytyltrimethylammoniumbromide (iii)NON-IONIC DETERGENTS- They does not contain any ions. Some liquid dishwashing detergents which are of non-ionic type .
17. BIODEGREDABLE DETERGENTS- The detergents which are linear and can be attacked by micro-organisms are biodegradable. Eg -sodium 4-(1-dodecyl) benzene \ sulphonate.
18. NON-BIODEGREDABLE DETERGENTS- The detergents which are branched and cannot be decomposed by micro-organisms are called non-biodegdradable.eg-sodium 4-(1,3,5,7 tetramethyloctl)-benzene sulphonate .It creates water pollution.
VERY SHORT ANSWER TYPE QUESTION (1 marks)
Q-1 Define the term chemotherapy? Ans-1 Treatment of diseases using chemicals is called chemotherapy.
Q-2 why do we require artificial sweetening agents? Ans-2 To reduce calorie intake.
Q-3 what are main constiuent of Dettol? Ans-3 Choloroxylenol & Terpinol .
Q-4 what type drug phenaticinis? Ans-4 It is antipyretics.
Q-5 Name the drug that are used to control allergy? Ans-5 Antihistamines.
Q-6Why is the use of aspartame limited to cold food and drinks? Ans-6 It is unstable at cooking temperature and decompose.
Q-7What is tranquilizers? Give an example? Ans-7 They is the drug used in stress, mild severe mental disease.
Q-8 what type of drug chloramphenicol? Ans-8 It is broad spectrum antibiotic.
Q-9Why is biothional is added to the toilet soap? Ans-9It acts as antiseptics.
Q-10 what are food preservatives? Ans-10 The substances that prevent spoilage of food due to microbial growth. eg- sodium benzonate.
SHORT ANSWER TYPE QUESTION (2 marks)
Q-1 Mention one important use of the following- (i) Equanil (ii)Sucrolose Ans-1 (i) Equanil- It is a tranquilizer. (ii) Sucrolose-It is an artificial sweetener.
Q-2 Define the following and give one example- (i)Antipyretics (ii) Antibiotics Ans-2 (i) Antipyretics- Those drugs which reduce the temperature of feveral body are called Antipyretics. Eg - Paracetamol (ii) Antibiotics-The drugs which prevent the growth of other micro-organisms. Eg- Pencillin.
Q-3 Name the medicines used for the treatment of the following- (i) Tuberculosis (ii) Typhoid Tuberculosis- Sterptomycin Typhoid- Cholororophenicol
Q-4 what are tincture of iodine? Ans-4 2-3% iodine solution of alcohol water is called tincture of Iodine. It is a powerful antiseptics and is applied on wounds.
Q- 5 What is artificial sweetening agent? Give two examples? Ans-5 The substances which give sweetening to food but don’t add calorie to our body . Eg- Saccharin, alitame.
Q-6 How is synthetic detergents better than soaps? Ans- 6 (i) Detergents can be used in hard water but soaps cannot be used. (ii) Detergents have a stronger cleansing action than soaps.
Q-7 what are sulpha drugs? Give two examples? Ans-7 a group of drugs which are derivatives of sulphanilamide and are used in place of antibiotics is called sulpha drugs. Eg- sulphadizine, sulphanilamide.
Q-8 what forces are involved in holding the active sites of the enzymes? Ans-8 The forces are involved in holding the active sites of the enzymes are hydrogen bonding , ionic bonding , dipole-dipole attractions or Vander waals force of attractions.
Q-9 Describe the following giving an example in each case- (i) Edible colours (ii) Antifertility drugs (i) Edible colours- They are used for dying food. Eg- saffron is used to colour rice. (ii) Antifertility drugs- Those drugs which control the birth of the child are called antifertility drugs.
Q-10 Give two examples of organic compounds used as antiseptics? Ans-10 Phenol (0.2%), iodoform SHORT ANSWER TYPE QUESTION (3 marks)
Q-1 what are Biodegredable and non-biodegdredable detergents? Give one example of each. Ans-1 Detergents having straight hydrocarbon chain and are easily decomposed by micro-organisms are called Biodegredable detergents.The detergents having branched hydrocarbon chain and are not easily decomposed by micro-organisms are called Non-Biodegredable detergents.
Q-2 what are barbiturates? To which class of drugs do they belong? Give two examples. Ans-2 Derivatives of barbituric acid are called barbiturates.They are tranquilizers. They also act as hypnotics. eg- luminal , seconal.
Q-3 what is the use of – (i) Benadryl (ii) sodium benzoate (iii) Progesterone Ans-3 (i) Antihistamines (ii) Preservatives (iii) Antifertility drug
Q-4 Identify the type of drug- (i) Ofloxacin (ii) Aspirin (iii) Cimetidine Ans- 4 (i) Antibiotic (ii) Analgesics & Antipyretics (iii) Antihistamines & antacid
Q-5 Describe the following with suitable example- (i) Disinfectant (ii) Analgesics (iii) Broad spectrum antibiotics (i) Disinfectant- chemicals used to kill the micro-organisms can applied on non living articles. (ii) Analgesics- They are the drugs which are used to relieve pain . eg – Aspirin , Ibuprofen. (iii) Broad spectrum antibiotics- They kill the wide range of gram positive and gram negative bacteria. Eg- Chloramphenicol , ofloxacin.
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