Class 10th Science Gujarat Board Solution
Exercise- What is called the compounds possessing (-CHO) functional group ?A. Amide B. Aldehyde C.…
- Which functional group is possessed by carboxylic acid ?A. B. -COOH C. -CHO D. -OH…
- ‘ol’ suffix is attached with which group in nomenclature?A. -CHO B. C. -OH D. -X…
- Which functional group is there in methyl ethanoate ?A. Alcohol B. Halide C. Ketone D.…
- Which of the following compounds is obtained by fermentation reaction of molasses ?A.…
- What is called the solution ethanol containing 5% water ?A. Beer B. Varnish C. Rectified…
- What is the molecular formula of formalin?A. HCOOH B. HCOOCH3 C. HCHO D. HCOOC2H5…
- Which substance is obtained by reduction of methanal ?A. Ethanol B. CO2 and O2 C. Methanol…
- What is prepared by Fisher-Tropsch method ?A. Acetic acid B. Acetaldehyde C. Acetone D.…
- Which of the following is the use of propanone ?A. To remove nail polish B. Antiseptic C.…
- Which of the following is the reaction occurring between alcohol and carboxylic acid in…
- Which compound of the following functional groups is having minimum three carbon atoms ?A.…
- Which of the following monomers is in polythene ?A. CH3-CH3 B. CH2 + Ch = CH3 C. CH2 = CH2…
- Which of the following is the use of acetic acid ?A. Preparation of vinegar B. White lead…
- Which of the following is used in conveyor belts ?A. Polythene B. PVC C. Teflon D.…
- Mention the functional groups containing oxygen.
- Explain the fermentation reaction and its importance.
- Write preparation of methanol with equation.
- Write properties of methanal.
- Write Fisher-Tropsch method with equation.
- Write preparation of ethanoic acid.
- Write the definition of functional group and give examples of two functional groups.…
- Explain homopolymer and co-polymers.
- Explain addition and condensation polymers.
- Write structures and uses of ethene and vinyl chloride polymer.
- Write uses of polymers.
- Write the structure and uses of Teflon and polyisoprene polymers.…
- Write industrial production of ethanol.
- Write properties of ethanol.
- What is rubber ? Explain.
- Write uses of ethanol.
- Give examples of aldehyde and ketone.
- Write oxidation, reduction and addition reaction of methanal with hydrogen cyanide.…
- Write uses of acetone.
- Write uses of ethanoic acid.
- What is meant by soap? Write its preparation.
- What is called esterification reaction ? Explain giving examples.…
- Write names and molecular formulas of first four members of alkanes and their…
- Write four chemical properties of ethanol.
- “Alcohol is harmful as drink.” Explain this statement in detail.
- Write uses of methanal (formaldehyde).
- Write properties of propanone.
- Write properties of ethanoic acid.
- What is polymer? Explain in detail.
- Write a short note on detergents.
- Write in detail classification of polymers.
- Write short notes-polyester and polyamide.
- Write about vulcanised rubber and its uses.
- What is called the compounds possessing (-CHO) functional group ?A. Amide B. Aldehyde C.…
- Which functional group is possessed by carboxylic acid ?A. B. -COOH C. -CHO D. -OH…
- ‘ol’ suffix is attached with which group in nomenclature?A. -CHO B. C. -OH D. -X…
- Which functional group is there in methyl ethanoate ?A. Alcohol B. Halide C. Ketone D.…
- Which of the following compounds is obtained by fermentation reaction of molasses ?A.…
- What is called the solution ethanol containing 5% water ?A. Beer B. Varnish C. Rectified…
- What is the molecular formula of formalin?A. HCOOH B. HCOOCH3 C. HCHO D. HCOOC2H5…
- Which substance is obtained by reduction of methanal ?A. Ethanol B. CO2 and O2 C. Methanol…
- What is prepared by Fisher-Tropsch method ?A. Acetic acid B. Acetaldehyde C. Acetone D.…
- Which of the following is the use of propanone ?A. To remove nail polish B. Antiseptic C.…
- Which of the following is the reaction occurring between alcohol and carboxylic acid in…
- Which compound of the following functional groups is having minimum three carbon atoms ?A.…
- Which of the following monomers is in polythene ?A. CH3-CH3 B. CH2 + Ch = CH3 C. CH2 = CH2…
- Which of the following is the use of acetic acid ?A. Preparation of vinegar B. White lead…
- Which of the following is used in conveyor belts ?A. Polythene B. PVC C. Teflon D.…
- Mention the functional groups containing oxygen.
- Explain the fermentation reaction and its importance.
- Write preparation of methanol with equation.
- Write properties of methanal.
- Write Fisher-Tropsch method with equation.
- Write preparation of ethanoic acid.
- Write the definition of functional group and give examples of two functional groups.…
- Explain homopolymer and co-polymers.
- Explain addition and condensation polymers.
- Write structures and uses of ethene and vinyl chloride polymer.
- Write uses of polymers.
- Write the structure and uses of Teflon and polyisoprene polymers.…
- Write industrial production of ethanol.
- Write properties of ethanol.
- What is rubber ? Explain.
- Write uses of ethanol.
- Give examples of aldehyde and ketone.
- Write oxidation, reduction and addition reaction of methanal with hydrogen cyanide.…
- Write uses of acetone.
- Write uses of ethanoic acid.
- What is meant by soap? Write its preparation.
- What is called esterification reaction ? Explain giving examples.…
- Write names and molecular formulas of first four members of alkanes and their…
- Write four chemical properties of ethanol.
- “Alcohol is harmful as drink.” Explain this statement in detail.
- Write uses of methanal (formaldehyde).
- Write properties of propanone.
- Write properties of ethanoic acid.
- What is polymer? Explain in detail.
- Write a short note on detergents.
- Write in detail classification of polymers.
- Write short notes-polyester and polyamide.
- Write about vulcanised rubber and its uses.
Exercise
Question 1.What is called the compounds possessing (-CHO) functional group ?
A. Amide
B. Aldehyde
C. Ketone
D. Alcohol
Answer:The compounds which have -CHO group are called aldehydes.
Ex- CH3-CH2-CHO is an aldehyde. Its common name is propionaldehyde and IUPAC name is propanal.
Question 2.Which functional group is possessed by carboxylic acid ?
A. 
B. –COOH
C. –CHO
D. -OH
Answer:The compounds which have -COOH group are called carboxylic acids.
Ex- CH3-COOH is a carboxylic acid. Its common name is acetic acid and IUPAC name is ethanoic acid.
Question 3.‘ol’ suffix is attached with which group in nomenclature?
A. –CHO
B.
C. –OH
D. –X
Answer:The compounds which have -OH group are called alcohols. And we use ‘hydroxy’ as prefix and ‘ol’ as suffix in nomenclature.
Ex- CH3-CH2-OH is an alcohol. Its common name is ethyl alcohol and IUPAC name is ethanol.
Question 4.Which functional group is there in methyl ethanoate ?
A. Alcohol
B. Halide
C. Ketone
D. Ester
Answer:The general molecular formula of ester is R’COOR. And the molecular formula of methyl ethanoate is CH3COOCH3.So it is an ester.
Question 5.Which of the following compounds is obtained by fermentation reaction of molasses ?
A. Chloromethane
B. Ethanol
C. Acetone
D. All the given
Answer:Fermentation is a process in which sugar or molasses is converted into ethanol and CO2 gas by enzymes. It is an anaerobic process (In such reactions, presence of oxygen is not necessary). In this reaction, sugar or molasses first converted into glucose and fructose by enzyme invertase. And then glucose and fructose converted into ethanol and CO2 gas by enzyme zymase.
C12H22O11 + H2O 
C6H12O6 + C6H12O6
C6H12O6
2C2H5OH + 2CO2
Question 6.What is called the solution ethanol containing 5% water ?
A. Beer
B. Varnish
C. Rectified spirit
D. Perfume
Answer:Ethanol solution containing 5% water is called rectified spirit which is used for making the outer surface of body germ-free.
Question 7.What is the molecular formula of formalin?
A. HCOOH
B. HCOOCH3
C. HCHO
D. HCOOC2H5
Answer:The aqueous solution of formaldehyde is called formalin. So the molecular formula of formalin is HCHO.
Question 8.Which substance is obtained by reduction of methanal ?
A. Ethanol
B. CO2 and O2
C. Methanol
D. All the given
Answer:The addition of hydrogen and removal of oxygen in a compound is called reduction. So when methanal will react to hydrogen gas (H2) in the presence of palladium (Pd) catalyst then methanal gets reduced into methanol and methanol is obtained.
HCHO + H2
CH3OH
Question 9.What is prepared by Fisher-Tropsch method ?
A. Acetic acid
B. Acetaldehyde
C. Acetone
D. Ethano
Answer:In Fisher-Tropsch method, when mixture of ethene and water gas is passed over a catalyst cobalt oxide (CaO) at 150 bar pressure 453 K temperature then acetone is obtained.
CH2=CH2 + H2 + CO 
CH3COCH3
Question 10.Which of the following is the use of propanone ?
A. To remove nail polish
B. Antiseptic
C. Antibiotic
D. As preservative
Answer:Acetone is used to remove nail polish.
Question 11.Which of the following is the reaction occurring between alcohol and carboxylic acid in presence of concentrated H2SO4?
A. Hydrolysis
B. Beta-elimination
C. Saponification
D. Esterification
Answer:Ethanoic acid reacts with ethanol in presence of concentrated sulphuric acid and forms ethyl ethanoate (ethyl acetate). This reaction of formation of ester by the reaction of carboxylic acid with alcohol is called esterification.
CH3COOH+C2H5OH
CH3COOC2H5 + H2
Question 12.Which compound of the following functional groups is having minimum three carbon atoms ?
A. –COOH
B. –CHO
C.
D. –C-O-
Answer:The compound of ketone functional group which is having minimum three carbon atoms is acetone. The molecular formula of acetone is CH3COCH3.
Question 13.Which of the following monomers is in polythene ?
A. CH3-CH3
B. CH2 + Ch = CH3
C. CH2 = CH2
D. CH = CH
Answer:The monomer of polythene is ethene. Polythene is made of repeated unit of ethene by the process of polymerisation.
Question 14.Which of the following is the use of acetic acid ?
A. Preparation of vinegar
B. White lead
C. As reactant (reagent)
D. All the given
Answer:Acetic acid is used in the preparation of vinegar and white lead. And acetic acid is also used as a solvent and reagent in the laboratory.
Question 15.Which of the following is used in conveyor belts ?
A. Polythene
B. PVC
C. Teflon
D. Neoprene
Answer:There are five main materials that conveyor belts are made out of: thermoplastics, metal, rubber, fabric and leather. Plastics include polyester, polyvinyl chloride, silicone and polyethylene. So out of the following, PVC is used in conveyor belts.
Question 16.Mention the functional groups containing oxygen.
Answer:The functional groups containing oxygen are:
Alcohol(R-OH), ether(R-O-R), aldehyde(R-CHO), ketone(R-CO-R), carboxylic acid(R-COOH), amide(R-CONH2), ester(R-COO-R) and acid halide(R-COCl).
Question 17.Explain the fermentation reaction and its importance.
Answer:Fermentation is a process in which sugar or molasses is converted into ethanol and CO2 gas by enzymes. It is an anaerobic process (In such reactions, presence oxygen is not necessary). In this reaction, sugar or molasses first converted into glucose and fructose by enzyme invertase. And then glucose and fructose converted into ethanol and CO2 gas by enzyme zymase.
C12H22O11 + H2O C6H12O6 + C6H12O6
C6H12O62C2H5OH + 2CO2
Since fermentation reaction does not require heat, fermentation retains enzymes, vitamins and other nutrients that are usually destroyed by food processing.
Question 18.Write preparation of methanol with equation.
Answer:Methanol is prepared by reduction of methanal. When methanal reacts to hydrogen gas (H2) in the presence of palladium (Pd) catalyst then methanal gets reduced into methanol and methanol is formed.
HCHO + H2CH3OH
Question 19.Write properties of methanal.
Answer:1. Methanal is a colourless, poisonous gas. Its boiling point is 253 K. It is soluble in water.
2. Methanoic acid is formed by the oxidation of methanal in presence of oxidising agent.
HCHO 
HCOOH
3. Methanol is formed by reduction of methanal.
HCHO + H2CH3OH
4. On addition of HCN to methanal then methanal cyanohydrin is formed.
H-CHO + H-CN → H-CHOH-CN
Question 20.Write Fisher-Tropsch method with equation.
Answer:Fisher-Tropsch method is a method of preparation of acetone. In Fisher-Tropsch method, when a mixture of ethene and water gas is passed over a catalyst cobalt oxide (CaO) at 150 bar pressure 453 K temperature then acetone is obtained.
CH2=CH2 + H2 + CO CH3COCH3
Question 21.Write preparation of ethanoic acid.
Answer:(1) Ethanoic acid is formed by oxidation of ethanol in air by fermentation in presence of acetobacter enzyme.
C2H5OH + O2
CH3COOH + H2O
(2) On the industrial production of ethanoic acid, methanol is reacted with carbon monoxide in presence of catalyst Iodine-Rhodium (I2-Rh).
CH3OH + CO 
CH3COOH
Question 22.Write the definition of functional group and give examples of two functional groups.
Answer:The atom or group of atoms by which properties of organic compounds are determined, that atom or group of atoms is called the functional group.
Ex- Alcohol(-OH) and aldehyde(-CHO).
Question 23.Explain homopolymer and co-polymers.
Answer:1. Homopolymer- When two or more types of simple organic monomers of the same type combine with one another through chemical bond formation gives polymers then these polymers are called homopolymer.
Ex- Polythene is a homopolymer which is prepared of ethene.
2. Co-polymer- When two or more types of simple organic monomers of the different type combine with one another through chemical bond formation gives polymers then these polymers are called co-polymer.
Ex- Styrene Butadiene Rubber is a co-polymer which is prepared from styrene and butadiene.
Question 24.Explain addition and condensation polymers.
Answer:1. Addition polymers- The polymers which are formed by combination of chemical bond formation of simple organic monomers having double bond are called addition polymer.
Ex- Polystyrene is an addition polymer which is prepared from styrene.
2. Condensed polymers- When two different types of simple monomers combine with one another by condensed polymerisation and give polymers after removal of molecules like water, ammonia or alcohol are called condensed polymers.
Ex- Nylon6,6 is a condensed polymer which is obtained from hexamethylene diamine and adipic acid.
Question 25.Write structures and uses of ethene and vinyl chloride polymer.
Answer:Polythene- The polymer of ethene is polythene (-CH2—CH2-)n.
Use- It is used in toys and packing bags.
Polyvinyl Chloride- The polymer of vinyl chloride is polyvinyl chloride.
Use- It is used in the preparation of flooring tiles, raincoats and handbags.
Question 26.Write uses of polymers.
Answer:Polymers are used in preparation of utensils for household purposes, pipes, paints, fibres, nylon, terylene, spare parts of automobile, furniture and brush, comb, chappal, raincoat, etc. It is also useful in the preparation of fishnets, ropes and tyres. It is useful in the textile industry.
Question 27.Write the structure and uses of Teflon and polyisoprene polymers.
Answer:Teflon- It is a polymer which is obtained from tetrafluoroethene (CF2=CF2).
Use- It is used in the preparation of non-stick cooking vessels and as an insulator.
Polyisoprene- It is a polymer which is obtained from isoprene.
Use- Gum polyisoprene compounds are used in rubber bands, cut thread, baby bottle nipples, and other such items.
Question 28.Write industrial production of ethanol.
Answer:1. Industrial production of ethanol by fermentation process- Fermentation is a process in which sugar or molasses is converted into ethanol and CO2 gas by enzymes. It is an anaerobic process (In such reactions, presence oxygen is not necessary). In this reaction, sugar or molasses first converted into glucose and fructose by enzyme invertase. And then glucose and fructose converted into ethanol and CO2 gas by enzyme zymase.
C12H22O11 + H2O C6H12O6 + C6H12O6
C6H12O62C2H5OH + 2CO2
2. Modern method of Industrial production of Ethanol- In this method, the industrial production of ethanol is carried out by hydration of ethene in the presence of concentrated sulphuric acid.
CH2=CH2 + H2O CH3CH2OH
Question 29.Write properties of ethanol.
Answer:The properties of ethanol are:
(1) Pure ethanol is colourless. Its boiling point is 351 K and it is highly soluble in water.
(2) It is very combustible liquid. It burns rapidly with blue flame and produces carbon dioxide and water.
C2H5OH + 3O2
2CO2 + 3H2O
(3) Ethanol reacts with sodium metal then sodium ethoxide and dihydrogen gas are produced.
2C2H5OH + 2Na 2C2H5ONa + H2
(4) Ethanol on reaction with acetic acid in presence of acid gives ethyl acetate which has a fruity smell. This reaction is called esterification.
CH3COOH + C2H5OH 
CH3COOC2H5 + H2O
Question 30.What is rubber ? Explain.
Answer:Rubber is a polymer with the property of elasticity. There are two categories of rubber: natural rubber obtained from the rubber tree and synthetic rubber derived from petrochemicals. The characteristic property of elasticity of natural rubber is maintained between temperatures 283 K to 333 K or higher. At the temperature below 283 K, it remains brittle while it becomes soft at temperatures 333 K or higher. Due to property of elasticity, it is used in many fields.
Question 31.Write uses of ethanol.
Answer:The uses of ethanol are:
(1) It is used as solvent in industry, varnish, and in fragrant materials like perfume and in medicine also.
(2) As it is antiseptic, it is used for dressing and cleaning of boils.
(3) Ethanol solution containing 5% water is called rectified spirit which is useful for making the outer surface of the body germ-free.
Question 32.Give examples of aldehyde and ketone.
Answer:Examples of aldehyde are:
Formaldehyde (HCHO), Acetaldehyde (CH2-CHO), Propionaldehyde (CH3-CH2-CHO)
Examples of ketone are:
Acetone (CH3-CO-CH3)
Methyl ethyl ketone (CH3-CH2-CO-CH3)
Question 33.Write oxidation, reduction and addition reaction of methanal with hydrogen cyanide.
Answer:(1) Oxidation: Methanoic acid is formed by oxidation of methanal in presence of oxidising agent.
HCHO HCOOH
(2) Reduction: Methanol is prepared by reduction when methanal reacts with dihydrogen (H2) gas in the presence of palladium catalyst.
HCHO + H2CH3OH
(3) Addition reaction of methanal with hydrogen cyanide- On addition of HCN to methanal then methanal cyanohydrin is formed.
H-CHO + H-CN H-CHOH-CN
Question 34.Write uses of acetone.
Answer:Uses of acetone are:
1. It is used as a solvent in the laboratory and in the paint industry.
2. It is used in the preparation of artificial leather and synthetic fibres.
3. It is used to remove nail paint.
Question 35.Write uses of ethanoic acid.
Answer:Uses of ethanoic acid are:
1. It is used in the preparation of vinegar.
2. It is used as a solvent and reagent in the laboratory.
3. It is used in the preparation of white lead.
Question 36.What is meant by soap? Write its preparation.
Answer:Soap is a sodium or potassium salt of fatty acid (stearic acid, oleic acid, palmitic acid). Sodium salt is present in washing soaps and potassium salt is present in bathing soaps.
Preparation of Soap-When vegetable oil (groundnut oil) or animal fat heated with sodium hydroxide (NaOH) then sodium salt of fatty acid and glycerol are formed. This process of preparing soap is called saponification.
Vegetable oil or animal fat + Sodium hydroxide 
Glycerol + Sodium salt of fatty acid (soap)
Question 37.What is called esterification reaction ? Explain giving examples.
Answer:When ethanoic acid reacts with ethanol in presence of concentrated sulphuric acid and forms ethyl ethanoate (ethyl acetate). This reaction of formation of ester by the reaction of carboxylic acid with alcohol is called esterification reaction.
CH3COOH+C2H5OH
CH3COOC2H5 + H2
Question 38.Write names and molecular formulas of first four members of alkanes and their corresponding alcohols.
Answer:1. Alkane- Methane(CH4)
Alcohol- Methanol(CH3OH)
2. Alkane- Ethane(C2H6)
Alcohol- Ethanol
(CH3CH2OH)
3. Alkane- Propane(C3H8)
Alcohol- Propanol
(CH3CH2CH2OH)
4. Alkane- Butane(C4H10)
Alcohol- Butanol
(CH3CH2CH2CH2OH)
Question 39.Write four chemical properties of ethanol.
Answer:The chemical properties are:
(1) It is very combustible liquid. It burns rapidly with blue flame and produces carbon dioxide and water.
C2H5OH + 3O2 2CO2 + 3H2O
(2) Ethanol reacts with sodium metal then sodium ethoxide and dihydrogen gas are produced.
2C2H5OH + 2Na 2C2H5ONa + H2
(3) Ethanol on reaction with acetic acid in presence of acid gives ethyl acetate which has a fruity smell. This reaction is called esterification.
CH3COOH + C2H5OH CH3COOC2H5 + H2O
(4) Acetic acid is formed by oxidation of ethanol.
CH3CH2OH
CH3COOH
Question 40.“Alcohol is harmful as drink.” Explain this statement in detail.
Answer:Ethanol is known as toxic amongst alcohols. Those who drink ethanol containing substances like methanol then they lose their eyesight and become blind. They lose sensitivity and loss the balance of the body. It affects the liver and causes death due to a disease called cirrhosis of liver. Hence the drinking of alcohol is harmful for the health.
Question 41.Write uses of methanal (formaldehyde).
Answer:Uses of methanal are:
(1) Aqueous solution of methanal (formalin) is antiseptic and so it is used to preserve dead animals.
(2) It is used as a raw material in plastic industry. Methanal is used as a monomer in preparation of Bakelite, melamine plastic etc.
(3) Methanal is used for making dyes, phenol and formaldehyde fibres(Polymer).
Question 42.Write properties of propanone.
Answer:Properties of propanone are:
(1) Propanone is a colourless liquid and has a fragrant smell. Its boiling point is 329 K and it is very much soluble in water.
(2) Propanone gives propan-2-ol on reduction with reducing agent like Sodium borohydride (NaBH4) or Lithium aluminium hydride (LiAlH4).
CH3COCH3
CH3-CHOH-CH3
(3) Ethanoic acid is obtained by oxidation of propanone, with alkaline potassium permanganate.
CH3COCH3
CH3COOH + CO2 + H2O
(4) On addition of HCN to propanone, it gives propanone cyanohydrin.
CH3COCH3 + HCN → CH3-COHCN-CH3
Question 43.Write properties of ethanoic acid.
Answer:Properties of ethanoic acid are:
(1) Ethanoic acid is a colourless, liquid containing sour smell and is soluble in water. Its boiling point is 391 K.
(2) Ethanoic acid reacts with metals like sodium and magnesium and forms metal ethanoate (acetate) salt and dihydrogen gas. It is a weak acid.
2CH3COOH + 2Na 
2CH3COONa + H2
(3) Ethanoic acid reacts with ethanol in presence of concentrated sulphuric acid and forms ethyl ethanoate (ethyl acetate).
CH3COOH + C2H5OH CH3COOC2H5 + H2
Question 44.What is polymer? Explain in detail.
Answer:The macromolecules which are formed by combination of one or more than two types of simple molecules by chemical bond formation are called polymers. The process of one or more than two types of simple molecules that combine by chemical bond formation is called polymerisation. Polythene is formed by addition reaction of molecules of ethene with one another. In this reaction, two molecules of monomer ethene combine in the first step and form a dimer. And when third molecule combines with dimer and forms a trimer. A trimer combines with fourth monomer and forms a tetramer. In the same way a long chain is formed which is called polymer.
Question 45.Write a short note on detergents.
Answer:Detergents are the sodium salt of sulphonic acids. In detergents, sulphonate
(-SO3Na+) functional group is attached to hydrocarbon chain. The cleansing effect of the detergent is more effective because Ca2+ and Mg2+ ions present in hard water do not give precipitates with ions which are in soluble form. They remain in the solution and so detergent is not used in more quantity. Hence the use of detergent has increased. There are two parts in the structure of detergent molecule. One part is long hydrocarbon chain is known as non-polar tail which attracts towards dirt or oily stain. While the other negatively charged part (-SO3-Na+) is known as head which attracts towards water molecules. Concentrated solution of detergent applied on dirt or oil stain then non-polar part is attracted by oily stain or dirt.
When polar part remains in water then it attracts towards water and the spherical structure is formed around stain is called micelle. The part on which detergent is applied is being dragged by water so that the water gets dirty and the surface becomes clean.
Question 46.Write in detail classification of polymers.
Answer:1. Classification of polymers:
(i) Naturally occurring Polymer- The polymers which found in nature are called naturally occurring polymers.
Ex- Starch, protein, rubber and nucleic acid.
(ii) Semisynthetic polymer- Semisynthetic polymers are obtained by chemical reaction with polymers occurring in nature. The rubber with improved properties obtained by vulcanization of natural rubber, is used in the formation of tyres.
(iii) Synthetic polymers- Synthetic polymers are man-made polymers.
Ex- Fibres, plastic and rubber.
2. Classification based on Polymerisation Reaction:
(i) Homopolymer- When two or more types of simple organic monomers of the same type combine with one another through chemical bond formation gives polymers then these polymers are called homopolymer.
Ex- Polythene is a homopolymer which is prepared of ethene.
(ii) Co-polymer- When two or more types of simple organic monomers of the different type combine with one another through chemical bond formation gives polymers then these polymers are called co-polymer.
Ex- Styrene Butadiene Rubber is a co-polymer which is prepared from styrene and butadiene.
(iii) Addition polymers- The polymers which are formed by combination of chemical bond formation of simple organic monomers having double bond are called addition polymer.
Ex- Polystyrene is an addition polymer which is prepared from styrene.
(iv) Condensed polymers- When two different types of simple monomers combine with one another by condensed polymerisation and gives polymers after removal of molecule like water, ammonia or alcohol are called condensed polymers.
Ex- Nylon6,6 is a condensed polymer which is obtained from hexamethylene diamine and adipic acid.
Question 47.Write short notes-polyester and polyamide.
Answer:(i) Polyester- Polyester have innumerable ester functional group containing repeating units. It is formed by combination of two hydroxyl and two carboxylic groups containing substances.
Polyester fibres are mixed with cotton fibres and used in textile industry.
(ii) Polyamide- Polyamide is a polymer which containing amide group. It can be prepared by condensation of diamine and carboxylic acid and it is known as nylon.
Question 48.Write about vulcanised rubber and its uses.
Answer:If the mixture of rubber and sulphur is heated at 373 K to413 K temperature then the required change in the required portion can be carried out. This process is known as vulcanization. This reaction is slow and so zinc oxide is added as addition substance and so the reaction becomes fast.
Vulcanised rubber has very good elasticity, very low water absorbing property.
Uses-
(i) The vulcanised rubber is used in rubber bands.
(ii) It is used in the preparation of tubes and tyres of vehicles.
What is called the compounds possessing (-CHO) functional group ?
A. Amide
B. Aldehyde
C. Ketone
D. Alcohol
Answer:
The compounds which have -CHO group are called aldehydes.
Ex- CH3-CH2-CHO is an aldehyde. Its common name is propionaldehyde and IUPAC name is propanal.
Question 2.
Which functional group is possessed by carboxylic acid ?
A.
B. –COOH
C. –CHO
D. -OH
Answer:
The compounds which have -COOH group are called carboxylic acids.
Ex- CH3-COOH is a carboxylic acid. Its common name is acetic acid and IUPAC name is ethanoic acid.
Question 3.
‘ol’ suffix is attached with which group in nomenclature?
A. –CHO
B.
C. –OH
D. –X
Answer:
The compounds which have -OH group are called alcohols. And we use ‘hydroxy’ as prefix and ‘ol’ as suffix in nomenclature.
Ex- CH3-CH2-OH is an alcohol. Its common name is ethyl alcohol and IUPAC name is ethanol.
Question 4.
Which functional group is there in methyl ethanoate ?
A. Alcohol
B. Halide
C. Ketone
D. Ester
Answer:
The general molecular formula of ester is R’COOR. And the molecular formula of methyl ethanoate is CH3COOCH3.So it is an ester.
Question 5.
Which of the following compounds is obtained by fermentation reaction of molasses ?
A. Chloromethane
B. Ethanol
C. Acetone
D. All the given
Answer:
Fermentation is a process in which sugar or molasses is converted into ethanol and CO2 gas by enzymes. It is an anaerobic process (In such reactions, presence of oxygen is not necessary). In this reaction, sugar or molasses first converted into glucose and fructose by enzyme invertase. And then glucose and fructose converted into ethanol and CO2 gas by enzyme zymase.
C12H22O11 + H2O C6H12O6 + C6H12O6
C6H12O62C2H5OH + 2CO2
Question 6.
What is called the solution ethanol containing 5% water ?
A. Beer
B. Varnish
C. Rectified spirit
D. Perfume
Answer:
Ethanol solution containing 5% water is called rectified spirit which is used for making the outer surface of body germ-free.
Question 7.
What is the molecular formula of formalin?
A. HCOOH
B. HCOOCH3
C. HCHO
D. HCOOC2H5
Answer:
The aqueous solution of formaldehyde is called formalin. So the molecular formula of formalin is HCHO.
Question 8.
Which substance is obtained by reduction of methanal ?
A. Ethanol
B. CO2 and O2
C. Methanol
D. All the given
Answer:
The addition of hydrogen and removal of oxygen in a compound is called reduction. So when methanal will react to hydrogen gas (H2) in the presence of palladium (Pd) catalyst then methanal gets reduced into methanol and methanol is obtained.
HCHO + H2CH3OH
Question 9.
What is prepared by Fisher-Tropsch method ?
A. Acetic acid
B. Acetaldehyde
C. Acetone
D. Ethano
Answer:
In Fisher-Tropsch method, when mixture of ethene and water gas is passed over a catalyst cobalt oxide (CaO) at 150 bar pressure 453 K temperature then acetone is obtained.
CH2=CH2 + H2 + CO CH3COCH3
Question 10.
Which of the following is the use of propanone ?
A. To remove nail polish
B. Antiseptic
C. Antibiotic
D. As preservative
Answer:
Acetone is used to remove nail polish.
Question 11.
Which of the following is the reaction occurring between alcohol and carboxylic acid in presence of concentrated H2SO4?
A. Hydrolysis
B. Beta-elimination
C. Saponification
D. Esterification
Answer:
Ethanoic acid reacts with ethanol in presence of concentrated sulphuric acid and forms ethyl ethanoate (ethyl acetate). This reaction of formation of ester by the reaction of carboxylic acid with alcohol is called esterification.
CH3COOH+C2H5OH CH3COOC2H5 + H2
Question 12.
Which compound of the following functional groups is having minimum three carbon atoms ?
A. –COOH
B. –CHO
C.
D. –C-O-
Answer:
The compound of ketone functional group which is having minimum three carbon atoms is acetone. The molecular formula of acetone is CH3COCH3.
Question 13.
Which of the following monomers is in polythene ?
A. CH3-CH3
B. CH2 + Ch = CH3
C. CH2 = CH2
D. CH = CH
Answer:
The monomer of polythene is ethene. Polythene is made of repeated unit of ethene by the process of polymerisation.
Question 14.
Which of the following is the use of acetic acid ?
A. Preparation of vinegar
B. White lead
C. As reactant (reagent)
D. All the given
Answer:
Acetic acid is used in the preparation of vinegar and white lead. And acetic acid is also used as a solvent and reagent in the laboratory.
Question 15.
Which of the following is used in conveyor belts ?
A. Polythene
B. PVC
C. Teflon
D. Neoprene
Answer:
There are five main materials that conveyor belts are made out of: thermoplastics, metal, rubber, fabric and leather. Plastics include polyester, polyvinyl chloride, silicone and polyethylene. So out of the following, PVC is used in conveyor belts.
Question 16.
Mention the functional groups containing oxygen.
Answer:
The functional groups containing oxygen are:
Alcohol(R-OH), ether(R-O-R), aldehyde(R-CHO), ketone(R-CO-R), carboxylic acid(R-COOH), amide(R-CONH2), ester(R-COO-R) and acid halide(R-COCl).
Question 17.
Explain the fermentation reaction and its importance.
Answer:
Fermentation is a process in which sugar or molasses is converted into ethanol and CO2 gas by enzymes. It is an anaerobic process (In such reactions, presence oxygen is not necessary). In this reaction, sugar or molasses first converted into glucose and fructose by enzyme invertase. And then glucose and fructose converted into ethanol and CO2 gas by enzyme zymase.
C12H22O11 + H2O C6H12O6 + C6H12O6
C6H12O62C2H5OH + 2CO2
Since fermentation reaction does not require heat, fermentation retains enzymes, vitamins and other nutrients that are usually destroyed by food processing.
Question 18.
Write preparation of methanol with equation.
Answer:
Methanol is prepared by reduction of methanal. When methanal reacts to hydrogen gas (H2) in the presence of palladium (Pd) catalyst then methanal gets reduced into methanol and methanol is formed.
HCHO + H2CH3OH
Question 19.
Write properties of methanal.
Answer:
1. Methanal is a colourless, poisonous gas. Its boiling point is 253 K. It is soluble in water.
2. Methanoic acid is formed by the oxidation of methanal in presence of oxidising agent.
HCHO HCOOH
3. Methanol is formed by reduction of methanal.
HCHO + H2CH3OH
4. On addition of HCN to methanal then methanal cyanohydrin is formed.
H-CHO + H-CN → H-CHOH-CN
Question 20.
Write Fisher-Tropsch method with equation.
Answer:
Fisher-Tropsch method is a method of preparation of acetone. In Fisher-Tropsch method, when a mixture of ethene and water gas is passed over a catalyst cobalt oxide (CaO) at 150 bar pressure 453 K temperature then acetone is obtained.
CH2=CH2 + H2 + CO CH3COCH3
Question 21.
Write preparation of ethanoic acid.
Answer:
(1) Ethanoic acid is formed by oxidation of ethanol in air by fermentation in presence of acetobacter enzyme.
C2H5OH + O2 CH3COOH + H2O
(2) On the industrial production of ethanoic acid, methanol is reacted with carbon monoxide in presence of catalyst Iodine-Rhodium (I2-Rh).
CH3OH + CO CH3COOH
Question 22.
Write the definition of functional group and give examples of two functional groups.
Answer:
The atom or group of atoms by which properties of organic compounds are determined, that atom or group of atoms is called the functional group.
Ex- Alcohol(-OH) and aldehyde(-CHO).
Question 23.
Explain homopolymer and co-polymers.
Answer:
1. Homopolymer- When two or more types of simple organic monomers of the same type combine with one another through chemical bond formation gives polymers then these polymers are called homopolymer.
Ex- Polythene is a homopolymer which is prepared of ethene.
2. Co-polymer- When two or more types of simple organic monomers of the different type combine with one another through chemical bond formation gives polymers then these polymers are called co-polymer.
Ex- Styrene Butadiene Rubber is a co-polymer which is prepared from styrene and butadiene.
Question 24.
Explain addition and condensation polymers.
Answer:
1. Addition polymers- The polymers which are formed by combination of chemical bond formation of simple organic monomers having double bond are called addition polymer.
Ex- Polystyrene is an addition polymer which is prepared from styrene.
2. Condensed polymers- When two different types of simple monomers combine with one another by condensed polymerisation and give polymers after removal of molecules like water, ammonia or alcohol are called condensed polymers.
Ex- Nylon6,6 is a condensed polymer which is obtained from hexamethylene diamine and adipic acid.
Question 25.
Write structures and uses of ethene and vinyl chloride polymer.
Answer:
Polythene- The polymer of ethene is polythene (-CH2—CH2-)n.
Use- It is used in toys and packing bags.
Polyvinyl Chloride- The polymer of vinyl chloride is polyvinyl chloride.
Use- It is used in the preparation of flooring tiles, raincoats and handbags.
Question 26.
Write uses of polymers.
Answer:
Polymers are used in preparation of utensils for household purposes, pipes, paints, fibres, nylon, terylene, spare parts of automobile, furniture and brush, comb, chappal, raincoat, etc. It is also useful in the preparation of fishnets, ropes and tyres. It is useful in the textile industry.
Question 27.
Write the structure and uses of Teflon and polyisoprene polymers.
Answer:
Teflon- It is a polymer which is obtained from tetrafluoroethene (CF2=CF2).
Use- It is used in the preparation of non-stick cooking vessels and as an insulator.
Polyisoprene- It is a polymer which is obtained from isoprene.
Use- Gum polyisoprene compounds are used in rubber bands, cut thread, baby bottle nipples, and other such items.
Question 28.
Write industrial production of ethanol.
Answer:
1. Industrial production of ethanol by fermentation process- Fermentation is a process in which sugar or molasses is converted into ethanol and CO2 gas by enzymes. It is an anaerobic process (In such reactions, presence oxygen is not necessary). In this reaction, sugar or molasses first converted into glucose and fructose by enzyme invertase. And then glucose and fructose converted into ethanol and CO2 gas by enzyme zymase.
C12H22O11 + H2O C6H12O6 + C6H12O6
C6H12O62C2H5OH + 2CO2
2. Modern method of Industrial production of Ethanol- In this method, the industrial production of ethanol is carried out by hydration of ethene in the presence of concentrated sulphuric acid.
CH2=CH2 + H2O CH3CH2OH
Question 29.
Write properties of ethanol.
Answer:
The properties of ethanol are:
(1) Pure ethanol is colourless. Its boiling point is 351 K and it is highly soluble in water.
(2) It is very combustible liquid. It burns rapidly with blue flame and produces carbon dioxide and water.
C2H5OH + 3O2 2CO2 + 3H2O
(3) Ethanol reacts with sodium metal then sodium ethoxide and dihydrogen gas are produced.
2C2H5OH + 2Na 2C2H5ONa + H2
(4) Ethanol on reaction with acetic acid in presence of acid gives ethyl acetate which has a fruity smell. This reaction is called esterification.
CH3COOH + C2H5OH CH3COOC2H5 + H2O
Question 30.
What is rubber ? Explain.
Answer:
Rubber is a polymer with the property of elasticity. There are two categories of rubber: natural rubber obtained from the rubber tree and synthetic rubber derived from petrochemicals. The characteristic property of elasticity of natural rubber is maintained between temperatures 283 K to 333 K or higher. At the temperature below 283 K, it remains brittle while it becomes soft at temperatures 333 K or higher. Due to property of elasticity, it is used in many fields.
Question 31.
Write uses of ethanol.
Answer:
The uses of ethanol are:
(1) It is used as solvent in industry, varnish, and in fragrant materials like perfume and in medicine also.
(2) As it is antiseptic, it is used for dressing and cleaning of boils.
(3) Ethanol solution containing 5% water is called rectified spirit which is useful for making the outer surface of the body germ-free.
Question 32.
Give examples of aldehyde and ketone.
Answer:
Examples of aldehyde are:
Formaldehyde (HCHO), Acetaldehyde (CH2-CHO), Propionaldehyde (CH3-CH2-CHO)
Examples of ketone are:
Acetone (CH3-CO-CH3)
Methyl ethyl ketone (CH3-CH2-CO-CH3)
Question 33.
Write oxidation, reduction and addition reaction of methanal with hydrogen cyanide.
Answer:
(1) Oxidation: Methanoic acid is formed by oxidation of methanal in presence of oxidising agent.
HCHO HCOOH
(2) Reduction: Methanol is prepared by reduction when methanal reacts with dihydrogen (H2) gas in the presence of palladium catalyst.
HCHO + H2CH3OH
(3) Addition reaction of methanal with hydrogen cyanide- On addition of HCN to methanal then methanal cyanohydrin is formed.
H-CHO + H-CN H-CHOH-CN
Question 34.
Write uses of acetone.
Answer:
Uses of acetone are:
1. It is used as a solvent in the laboratory and in the paint industry.
2. It is used in the preparation of artificial leather and synthetic fibres.
3. It is used to remove nail paint.
Question 35.
Write uses of ethanoic acid.
Answer:
Uses of ethanoic acid are:
1. It is used in the preparation of vinegar.
2. It is used as a solvent and reagent in the laboratory.
3. It is used in the preparation of white lead.
Question 36.
What is meant by soap? Write its preparation.
Answer:
Soap is a sodium or potassium salt of fatty acid (stearic acid, oleic acid, palmitic acid). Sodium salt is present in washing soaps and potassium salt is present in bathing soaps.
Preparation of Soap-When vegetable oil (groundnut oil) or animal fat heated with sodium hydroxide (NaOH) then sodium salt of fatty acid and glycerol are formed. This process of preparing soap is called saponification.
Vegetable oil or animal fat + Sodium hydroxide Glycerol + Sodium salt of fatty acid (soap)
Question 37.
What is called esterification reaction ? Explain giving examples.
Answer:
When ethanoic acid reacts with ethanol in presence of concentrated sulphuric acid and forms ethyl ethanoate (ethyl acetate). This reaction of formation of ester by the reaction of carboxylic acid with alcohol is called esterification reaction.
CH3COOH+C2H5OH CH3COOC2H5 + H2
Question 38.
Write names and molecular formulas of first four members of alkanes and their corresponding alcohols.
Answer:
1. Alkane- Methane(CH4)
Alcohol- Methanol(CH3OH)
2. Alkane- Ethane(C2H6)
Alcohol- Ethanol
(CH3CH2OH)
3. Alkane- Propane(C3H8)
Alcohol- Propanol
(CH3CH2CH2OH)
4. Alkane- Butane(C4H10)
Alcohol- Butanol
(CH3CH2CH2CH2OH)
Question 39.
Write four chemical properties of ethanol.
Answer:
The chemical properties are:
(1) It is very combustible liquid. It burns rapidly with blue flame and produces carbon dioxide and water.
C2H5OH + 3O2 2CO2 + 3H2O
(2) Ethanol reacts with sodium metal then sodium ethoxide and dihydrogen gas are produced.
2C2H5OH + 2Na 2C2H5ONa + H2
(3) Ethanol on reaction with acetic acid in presence of acid gives ethyl acetate which has a fruity smell. This reaction is called esterification.
CH3COOH + C2H5OH CH3COOC2H5 + H2O
(4) Acetic acid is formed by oxidation of ethanol.
CH3CH2OH CH3COOH
Question 40.
“Alcohol is harmful as drink.” Explain this statement in detail.
Answer:
Ethanol is known as toxic amongst alcohols. Those who drink ethanol containing substances like methanol then they lose their eyesight and become blind. They lose sensitivity and loss the balance of the body. It affects the liver and causes death due to a disease called cirrhosis of liver. Hence the drinking of alcohol is harmful for the health.
Question 41.
Write uses of methanal (formaldehyde).
Answer:
Uses of methanal are:
(1) Aqueous solution of methanal (formalin) is antiseptic and so it is used to preserve dead animals.
(2) It is used as a raw material in plastic industry. Methanal is used as a monomer in preparation of Bakelite, melamine plastic etc.
(3) Methanal is used for making dyes, phenol and formaldehyde fibres(Polymer).
Question 42.
Write properties of propanone.
Answer:
Properties of propanone are:
(1) Propanone is a colourless liquid and has a fragrant smell. Its boiling point is 329 K and it is very much soluble in water.
(2) Propanone gives propan-2-ol on reduction with reducing agent like Sodium borohydride (NaBH4) or Lithium aluminium hydride (LiAlH4).
CH3COCH3 CH3-CHOH-CH3
(3) Ethanoic acid is obtained by oxidation of propanone, with alkaline potassium permanganate.
CH3COCH3 CH3COOH + CO2 + H2O
(4) On addition of HCN to propanone, it gives propanone cyanohydrin.
CH3COCH3 + HCN → CH3-COHCN-CH3
Question 43.
Write properties of ethanoic acid.
Answer:
Properties of ethanoic acid are:
(1) Ethanoic acid is a colourless, liquid containing sour smell and is soluble in water. Its boiling point is 391 K.
(2) Ethanoic acid reacts with metals like sodium and magnesium and forms metal ethanoate (acetate) salt and dihydrogen gas. It is a weak acid.
2CH3COOH + 2Na 2CH3COONa + H2
(3) Ethanoic acid reacts with ethanol in presence of concentrated sulphuric acid and forms ethyl ethanoate (ethyl acetate).
CH3COOH + C2H5OH CH3COOC2H5 + H2
Question 44.
What is polymer? Explain in detail.
Answer:
The macromolecules which are formed by combination of one or more than two types of simple molecules by chemical bond formation are called polymers. The process of one or more than two types of simple molecules that combine by chemical bond formation is called polymerisation. Polythene is formed by addition reaction of molecules of ethene with one another. In this reaction, two molecules of monomer ethene combine in the first step and form a dimer. And when third molecule combines with dimer and forms a trimer. A trimer combines with fourth monomer and forms a tetramer. In the same way a long chain is formed which is called polymer.
Question 45.
Write a short note on detergents.
Answer:
Detergents are the sodium salt of sulphonic acids. In detergents, sulphonate
(-SO3Na+) functional group is attached to hydrocarbon chain. The cleansing effect of the detergent is more effective because Ca2+ and Mg2+ ions present in hard water do not give precipitates with ions which are in soluble form. They remain in the solution and so detergent is not used in more quantity. Hence the use of detergent has increased. There are two parts in the structure of detergent molecule. One part is long hydrocarbon chain is known as non-polar tail which attracts towards dirt or oily stain. While the other negatively charged part (-SO3-Na+) is known as head which attracts towards water molecules. Concentrated solution of detergent applied on dirt or oil stain then non-polar part is attracted by oily stain or dirt.
When polar part remains in water then it attracts towards water and the spherical structure is formed around stain is called micelle. The part on which detergent is applied is being dragged by water so that the water gets dirty and the surface becomes clean.
Question 46.
Write in detail classification of polymers.
Answer:
1. Classification of polymers:
(i) Naturally occurring Polymer- The polymers which found in nature are called naturally occurring polymers.
Ex- Starch, protein, rubber and nucleic acid.
(ii) Semisynthetic polymer- Semisynthetic polymers are obtained by chemical reaction with polymers occurring in nature. The rubber with improved properties obtained by vulcanization of natural rubber, is used in the formation of tyres.
(iii) Synthetic polymers- Synthetic polymers are man-made polymers.
Ex- Fibres, plastic and rubber.
2. Classification based on Polymerisation Reaction:
(i) Homopolymer- When two or more types of simple organic monomers of the same type combine with one another through chemical bond formation gives polymers then these polymers are called homopolymer.
Ex- Polythene is a homopolymer which is prepared of ethene.
(ii) Co-polymer- When two or more types of simple organic monomers of the different type combine with one another through chemical bond formation gives polymers then these polymers are called co-polymer.
Ex- Styrene Butadiene Rubber is a co-polymer which is prepared from styrene and butadiene.
(iii) Addition polymers- The polymers which are formed by combination of chemical bond formation of simple organic monomers having double bond are called addition polymer.
Ex- Polystyrene is an addition polymer which is prepared from styrene.
(iv) Condensed polymers- When two different types of simple monomers combine with one another by condensed polymerisation and gives polymers after removal of molecule like water, ammonia or alcohol are called condensed polymers.
Ex- Nylon6,6 is a condensed polymer which is obtained from hexamethylene diamine and adipic acid.
Question 47.
Write short notes-polyester and polyamide.
Answer:
(i) Polyester- Polyester have innumerable ester functional group containing repeating units. It is formed by combination of two hydroxyl and two carboxylic groups containing substances.
Polyester fibres are mixed with cotton fibres and used in textile industry.
(ii) Polyamide- Polyamide is a polymer which containing amide group. It can be prepared by condensation of diamine and carboxylic acid and it is known as nylon.
Question 48.
Write about vulcanised rubber and its uses.
Answer:
If the mixture of rubber and sulphur is heated at 373 K to413 K temperature then the required change in the required portion can be carried out. This process is known as vulcanization. This reaction is slow and so zinc oxide is added as addition substance and so the reaction becomes fast.
Vulcanised rubber has very good elasticity, very low water absorbing property.
Uses-
(i) The vulcanised rubber is used in rubber bands.
(ii) It is used in the preparation of tubes and tyres of vehicles.