Updated on: 2026-03-31 | Author: Rahul Patil

Science & Tech Part 1 Chapter 9 Carbon Compounds Solutions

Q1. Write the uses of ethanol.

Answer

Ethanol being a good solvent, it is used in medicines such as tincture iodine (solution of iodine and ethanol), cough mixture and also in many tonics.

Q2. Colorless ethanol is in liquid state at room temperature.

Colorless ethanol is in liquid state at room temperature- Right

Q3. _______ is one of the combustible components of L.P.G.

Propane is one of the combustible components of L.P.G.

Explanation:

LPG (Liquefied Petroleum Gas) mainly contains propane C3H8 and butane C4H10, which are highly flammable and used as fuels for cooking and heating. Methane and ethane are found in natural gas, while butanol is an alcohol, not a major LPG component.

Q4. As one ascends in any homologous series, physical properties change gradually.

As one ascends in any homologous series, physical properties change gradually- Right

Q5. At room temperature ethanol is _______.

At room temperature ethanol is liquid.

Q6. Benzene is a cyclic unsaturated hydrocarbon.

Benzene is a cyclic unsaturated hydrocarbon- Right

Q7. Carbon compounds contain only open chains of carbon atoms.

Carbon compounds contain only open chains of carbon atoms- Wrong

Q8. CH 3 –CH 2 –CHO : propanal : : CH 3 –COOH : _______

CH3–CH2–CHO : propanal : : CH3–COOH : ethanoic acid

Q9. Complete the following activity.

Diagram: Refer textbook

Q10. Complete the following activity. Boiling point of ethanol → General name of ethanol → Use of ethanol → Boiling point of ethanoic acid → Melting point of pure ethanoic acid →

Boiling point of ethanol → 78 °C
General name of ethanol → Ethyl alcohol
or spirit
Use of ethanol → As a solvent in medicines
Boiling point of ethanoic acid → 118 °C
Melting point of pure ethanoic acid → 17 °C

Q11. Complete the following chart by using examples given in brackets. (isobutylene, cyclohexane, propane, cyclohexene, cyclopentane, benzene, propyne, isobutane, propene) Straight chain hydrocarbons Branched chain hydrocarbons Cyclic hydrocarbons

Straight chain hydrocarbons Branched chain hydrocarbons Cyclic hydrocarbons
Propane Isobutylene Cyclohexane
Propyne Isobutane Cyclohexene
Propene   Cyclopentane
    Benzene

Q12. Complete the following table for homologous series of alcohols. Name Molecular formula Condensed structural formula Number of carbon atom Number of -CH 2 - units Boiling point °C Methanol CH 4 O CH 3 -OH 1 1 63 Ethanol C 2 H 6 O CH 3 –CH 2 -OH 2 2 78 Propanol C 3 H 8 O CH 3 –CH 2 –CH 2 -OH ______ ______ 97 Butanol C 4 H 10 O CH 3 –CH 2 –CH 2 –CH 2 –OH ______ ______ 118

Name Molecular formula Condensed structural formula Number of carbon atom Number of -CH2- units Boiling point °C
Methanol CH4O CH3-OH 1 1 63
Ethanol C2H6O CH3–CH2-OH 2 2 78
Propanol C3H8O CH3–CH2–CH2-OH 3 3 97
Butanol C4H10O CH3–CH2–CH2–CH2–OH 4 4 118

Q13. Complete the following table for the homologous series of alkanes. Name Molecular formula Condensed structural formula Number of carbon atom Number of -CH 2 - units Boiling point °C Methane CH 4 CH 4 1 1 -162 Ethane C 2 H 6 CH 3 –CH 3 2 2 -88.5 Propane C 3 H 8 CH 3 –CH 2 –CH 3 3 3 -42 Butane C 4 H 10 CH 3 –CH 2 –CH 2 –CH 3 ______ ______ 0 Pentane C 5 H 12 CH 3 –CH 2 –CH 2 –CH 2 –CH 3 ______ ______ 36 Hexane C 6 H 14 CH 3 –CH 2 –CH 2 –CH 2 –CH 2 –CH 3 ______ ______ 69

Name Molecular formula Condensed structural formula Number of carbon atom Number of -CH2- units Boiling point °C
Methane CH4 CH4 1 1 -162
Ethane C2H6 CH3–CH3 2 2 -88.5
Propane C3H8 CH3–CH2–CH3 3 3 -42
Butane C4H10 CH3–CH2–CH2–CH3 4 4 0
Pentane C5H12 CH3–CH2–CH2–CH2–CH3 5 5 36
Hexane C6H14 CH3–CH2–CH2–CH2–CH2–CH3 6 6 69

Q14. Complete the following table for homologous series of Alkenes. Name Molecular formula Condensed structural formula Number of carbon atom Number of -CH 2 - units Boiling point °C Ethene C 2 H 4 CH 2 = CH 2 2 0 -102 Propene C 3 H 6 CH 3 –CH = C H 2 3 1 -48 1-Butene C 4 H 8 CH 3 –CH 2 –CH = CH 2 ______ ______ -6.5 1-Pentene C 5 H 10 CH 3 –CH 2 –CH 2 –CH = C H 2 ______ ______ 30

Name Molecular formula Condensed structural formula Number of carbon atom Number of -CH2- units Boiling point °C
Ethene C2H4 CH2 = CH2 2 0 -102
Propene C3H6 CH3–CH = CH2 3 1 -48
1-Butene C4H8 CH3–CH2–CH = CH2 4 2 -6.5
1-Pentene C5H10 CH3–CH2–CH2–CH = CH2 5 3 30

Q15. Complete the following table with writing the correct structural formula and molecular formula. Straight chain of carbon atoms Structural formula Molecular formula Name C-C ______ ______ Ethane C-C-C-C ______ ______ Butane C-C-C-C-C-C-C- ______ C 7 H 16 ______ C-C-C-C-C-C-C-C ______ C 8 H 18 ______

Straight chain of carbon atoms Structural formula Molecular formula Name
C-C \[\begin{array}{cc}\ce{H}\phantom{...}\ce{H}\\
|\phantom{....}|\\\ce{H - C - C - H}\\
|\phantom{....}|\\\ce{H}\phantom{...}\ce{H}
\end{array}\]		 C2H6 Ethane
C-C-C-C \[\begin{array}{cc}
\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\\
|\phantom{....}|\phantom{....}|\phantom{....}|\\\ce{H - C - C - C - C - H}\\|\phantom{....}|\phantom{....}|\phantom{....}|\\
\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}
\end{array}\]		 C4H10 Butane
C-C-C-C-C-C-C- \[\begin{array}{cc}
\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\\
|\phantom{....}|\phantom{....}|\phantom{....}|\phantom{....}|\phantom{....}|\phantom{....}|\\
\ce{H - C - C - C - C - C - C - C - H}\\
|\phantom{....}|\phantom{....}|\phantom{....}|\phantom{....}|\phantom{....}|\phantom{....}|\\
\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\end{array}\]		 C7H16 Heptane
C-C-C-C-C-C-C-C \[\begin{array}{cc}
\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\\
|\phantom{....}|\phantom{....}|\phantom{....}|\phantom{....}|\phantom{....}|\phantom{....}|\phantom{....}|\\\ce{H - C - C - C - C - C - C - C - C - H}\\
|\phantom{....}|\phantom{....}|\phantom{....}|\phantom{....}|\phantom{....}|\phantom{....}|\phantom{....}|\\\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}
\end{array}\]		 C8H18 Octane

Q16. Complete the following table with writing IUPAC name of carbon compound. Sr. No. Common name Structural formula IUPAC Name 1. ethylene CH 2 = CH 2 2. acetylene HC ≡ CH 3. acetic acid CH 3 - COOH 4. methyl alcohol CH 3 - OH 5. ethyl alcohol CH 3 - CH 2 - OH 6. acetaldehyde CH 3 - CHO 7. acetone CH 3 - CO - CH 3 8. ethyl methyl ketone CH 3 - CO - CH 2 - CH 3 9. ethyl amine CH 3 - CH 2 - NH 2 10. n-propyl chloride CH 3 - CH 2 - CH 2 - Cl

Sr. No. Common name Structural formula IUPAC Name
1. ethylene CH2 = CH2 Ethene
2. acetylene HC ≡ CH Ethyne
3. acetic acid CH3 - COOH Ethanoic acid
4. methyl alcohol CH3 - OH Methanol
5. ethyl alcohol CH3 - CH2 - OH Ethanol
6. acetaldehyde CH3 - CHO Ethanal
7. acetone CH3 - CO - CH3 Propanone
8. ethyl methyl ketone CH3 - CO - CH2 - CH3 Butanone
9. ethyl amine CH3 - CH2 - NH2 Ethanamine
10. n-propyl chloride CH3 - CH2 - CH2 - Cl 1-Chloropropane

Q17. Complete the given chart with writing the correct functional group of carbon compounds. (Ester, Aldehyde, Ketone, Carboxylic acid, Alcohol, Ether) -O-H \[\begin{array}{cc} \ce{O}\phantom{..}\\ ||\phantom{..}\\ \ce{-C-H} \end{array}\] \[\begin{array}{cc} \ce{O}\\ ||\\ \ce{-C-} \end{array}\] \[\begin{array}{cc} \ce{O}\phantom{.....}\\ ||\phantom{.....}\\ \ce{-C-O-H} \end{array}\] -O- \[\begin{array}{cc} \ce{O}\phantom{..}\\ ||\phantom{..}\\ \ce{-C-O} \end{array}\] \[\begin{array}{cc} \ce{-N-H}\\ |\phantom{..}\\ \ce{H}\phantom{..} \end{array}\]

Alcohol -O-H
Aldehyde \[\begin{array}{cc}
\ce{O}\phantom{..}\\
||\phantom{..}\\
\ce{-C-H}
\end{array}\]
Ketone \[\begin{array}{cc}
\ce{O}\\
||\\
\ce{-C-}
\end{array}\]
Carboxylic
acid		 \[\begin{array}{cc}
\ce{O}\phantom{.....}\\
||\phantom{.....}\\
\ce{-C-O-H}
\end{array}\]
Ether -O-
Ester \[\begin{array}{cc}
\ce{O}\phantom{..}\\
||\phantom{..}\\
\ce{-C-O}
\end{array}\]
Amine

\[\begin{array}{cc}
\ce{-N-H}\\
|\phantom{..}\\
\ce{H}\phantom{..}
\end{array}\]

Q18. Cyclohexane : Cyclic hydrocarbon : : Isobutylene : _______

Cyclohexane : Cyclic hydrocarbon : : Isobutylene : Branched hydrocarbon

Q19. Cyclohexane is a branched chain type of hydrocarbon.

Cyclohexane is a branched chain type of hydrocarbon- Wrong

Q20. Distinguish between: Alkane - Alkene

  Alkane Alkene
1. Alkanes are saturated hydrocarbons. Alkenes are unsaturated hydrocarbons.
2. They have C−C single bonds. They have at least one C=C double bond.
3. They are characterized by the general formula is CnH2n+2. They are characterized by the general formula is CnH2n.
4. First member of homologous series is methane. First member of homologous series is ethene.

Q21. Distinguish between: Open chain hydrocarbons - Closed chain hydrocarbons

  Open chain hydrocarbons Closed chain hydrocarbons
1. In open chain hydrocarbons, carbon atoms are linked to form a continuous straight or branched chain. In closed chain hydrocarbons, carbon atoms are linked to form a ring structure.
2. They are not aromatic compounds. They can be aromatic compounds.
3. E.g. Propane, Isobutane E.g. Cyclohexane, Benzene

Q22. Distinguish between: Saturated hydrocarbons - Unsaturated hydrocarbons

  Saturated hydrocarbons Unsaturated hydrocarbons
1. Hydrocarbons having the carbon atoms linked to each other by single bonds are called saturated hydrocarbons. Hydrocarbons having at least one carbon-carbon double or triple bond are called unsaturated hydrocarbons.
2. On burning, saturated hydrocarbons give a clean, blue flame. On burning, unsaturated hydrocarbons give a yellow flame with lots of black smoke.
3. Saturated hydrocarbons do not decolourize bromine or iodine solutions. Unsaturated hydrocarbons decolourize bromine or iodine solutions.
4. Saturated hydrocarbons are less reactive. Unsaturated hydrocarbons are usually highly reactive.

Q23. Draw electron dot structure and line structure for a given molecule. Ethene

Diagram: Refer textbook

Q24. Draw electron dot structure and line structure for a given molecule. Hydrogen

Diagram: Refer textbook

Q25. Draw electron dot structure and line structure for a given molecule. Methane

Diagram: Refer textbook

Q26. Draw electron dot structure and line structure for a given molecule. Nitrogen

Diagram: Refer textbook

Q27. Draw electron dot structure and line structure for a given molecule. Oxygen

Diagram: Refer textbook

Q28. Ester is a sweet-smelling compound.

Ester is a sweet-smelling compound- Right

Q29. Ethanol is soluble in water in all proportions.

Ethanol is soluble in water in all proportions- Right

Q30. Explain covalent bond with example.

Answer

Diagram: Refer textbook

Q31. Explain the Catenation power.

Answer

Carbon has a unique ability to form strong covalent bonds with other carbon atoms; this results in the formation of big molecules. This property of carbon is called catenation power.

Due to the catenation power of carbon, the compounds formed may have long straight chains of carbon, branched chains of carbon or rings of carbon.

Q32. Explain the concept of heteroatoms with the help of examples.

Answer

Many carbon compounds are formed in which atoms of elements such as oxygen, nitrogen, sulphur, halogens, etc., substitute one or more hydrogen atoms in the hydrocarbon chain.

The atom of an element other than carbon and hydrogen which replaces one or more hydrogen atoms in the hydrocarbon chain is called a heteroatom.

The compound acquires specific chemical properties due to these hetero atoms or the groups of atoms that contain heteroatoms, irrespective of the length and nature of the carbon chain in that compound. Therefore, these hetero atoms or the groups of atoms containing hetero atoms are called functional groups.

E.g. In CH3OH, the functional group contains hetero atom ‘O’.

In CH3CH2Cl, the functional group contains hetero atom ‘Cl’.

Q33. Explain the following reaction with an example. Esterification

Answer

Diagram: Refer textbook

Q34. Explain the following reaction with an example. Substitution reaction

Answer

The reaction in which replacement of an atom or a group of atoms in a molecule by another atom or group of atoms takes place is called substitution reaction. The substitution reactions of alkanes with chlorine occur in presence of sunlight in which one or more hydrogen atoms of alkanes such as methane are replaced by chlorine atoms.

E.g. \[\ce{CH4 + Cl2 ->[Sunlight] CH3Cl + HCl}\]

Q35. Explain the following reaction with example. Addition reaction

Answer

The reaction in which the addition of a substance occurs across the carbon-carbon double or triple bond is called an addition reaction. Addition reactions occur in unsaturated hydrocarbons.

e.g.

\[\begin{array}{cc}

\phantom{................................}\ce{H}\phantom{...}\ce{H}\\

\phantom{................................}|\phantom{....}|\\

\ce{H - C = C - H \underset{\text{Hydrogen}}{+ H - H} ->[Ni/Pt] H - C - C - H}\\

|\phantom{.....}|\phantom{..........................}|\phantom{....}|\\

\ce{\phantom{.}\underset{\text{Ethene}}{H \phantom{...}H}}\phantom{.........................}

\ce{\underset{\text{Ethane}}{H \phantom{...}H}}

\end{array}\]

Q36. Explain the following reaction with an example. Saponification

Answer

Diagram: Refer textbook

Q37. Explain the following term with example. Reduction

Answer

A chemical reaction in which a substance gains hydrogen or loses oxygen is called a reduction reaction.

E.g. In the following reaction, ethylene (ethene) is reduced to ethane.

\[\ce{\underset{\text{Ethylene}}{H2C = CH2} ->[H2][Pt/Ni] \underset{\text{Ethane}}{CH3CH3}}\]

Q38. Explain the Structural isomerism term with example.

Answer

Diagram: Refer textbook

Q39. Find the odd one out and give its explanation.

Answer

Ozone

Explanation-

Ozone is inorganic while others are organic compounds.

Q40. Find the odd one out and give its explanation.

Answer

C2H2

Explanation-

Ethyne (C2H2) is a unsaturated hydrocarbon while others are saturated hydrocarbons.

Q41. Find the odd one out and give its explanation.

Answer

C2H4

Explanation-

Ethene (C2H4) is a unsaturated hydrocarbon while others are saturated hydrocarbons.

Q42. Find the odd one out and give its explanation.

Answer

CaCO3

Explanation-

Calcium carbonate (CaCO3) is an inorganic compound while others are organic compounds.

Q43. Find the odd one out and give its explanation.

Answer

Teflon

Explanation-

Teflon is a polymer while others are monomer units of respective polymers.

Q44. From the following hydrocarbon _______ is the cyclic hydrocarbon.

From the following hydrocarbon benzene is the cyclic hydrocarbon.

Q45. Generally _______ is called spirit.

Generally ethanol is called spirit.

Q46. Generally, the melting and boiling point of carbon compounds are found to be less than _______ °C.

Generally, the melting and boiling point of carbon compounds are found to be less than 300 °C.

Q47. Give a chemical reaction in which a catalyst is used.

Answer

E.g. In the hydrogenation of ethene, nickel or platinum is used as catalyst.

\[\begin{array}{cc}

\phantom{................................}\ce{H}\phantom{...}\ce{H}\\

\phantom{................................}|\phantom{....}|\\

\ce{H - C = C - H \underset{\text{Hydrogen}}{+ H - H} ->[Ni/Pt] H - C - C - H}\\

|\phantom{.....}|\phantom{..........................}|\phantom{....}|\\

\ce{\phantom{.}\underset{\text{Ethene}}{H \phantom{...}H}}\phantom{.........................}

\ce{\underset{\text{Ethane}}{H \phantom{...}H}}

\end{array}\]

Q48. In general, saturated compounds are more reactive than unsaturated compounds.

In general, saturated compounds are more reactive than unsaturated compounds- Wrong

Q49. In LPG, butane is a flammable component.

The statement is Right.

Explanation:

Liquefied Petroleum Gas (LPG) contains combustible butane and propane. Both extremely combustible gases are used as fuel in homes and factories.

Q50. Ketone : –CO– : : Ester : _______

Ketone : –CO– : : Ester : –COO–

Q51. Match the pairs. Group 'A' Group 'B' a. C 2 H 6 1. Unsaturated hydrocarbon b. C 2 H 2 2. Molecular formula of an alcohol c. CH 4 O 3. Saturated hydrocarbon d. C 3 H 6 4. Triple bond

Group 'A' Group 'B'
a. C2H6 1. Saturated hydrocarbon
b. C2H2 2. Triple bond
c. CH4O 3. Molecular formula of an alcohol
d. C3H6 4. Unsaturated hydrocarbon 

Q52. Match the columns. Group A Group B 1) Ether a) –OH 2) Ketone b) –O– 3) Ester c) –CO– 4) Alcohol d) –COO

Group A Group B
1) Ether b) –O–
2) Ketone c) –CO–
3) Ester d) –COO
4) Alcohol a) –OH

Q53. Match the columns. Group A Group B 1. Straight chain hydrocarbon a) Benzene 2. Branched chain hydrocarbon b) Propyne 3. Cyclic hydrocarbon c) Isobutylene

Group A Group B
1. Straight chain hydrocarbon b) Propyne
2. Branched chain hydrocarbon c) Isobutylene
3. Cyclic hydrocarbon a) Benzene

Q54. Number of valence electrons in a carbon atom is _______.

Number of valence electrons in a carbon atom is 4.

Q55. Observe the figure and write the answers to the following questions. Write the name of the reaction shown in the following figure. Write the above chemical reaction in the form of a balanced equation. Write the name of the product produced in the above reaction, write a use. Write the name of the catalyst used in the above reaction.

Answer

The reaction shown in the figure is esterification.

Balanced equation of the reaction between ethanol and ethanoic acid is as follows:

\[\ce{\underset{\text{Ethanol}}{C2H5OH} + \underset{\text{Ethanoic acid}}{CH3COOH} ->[Conc.][H2SO4] \underset{\text{Ethyl ethanoate}}{CH3COOC2H5} + \underset{\text{Water}}{H2O}}\]

The product formed is ethyl ethanoate.

Use: It is used for making fragrances and flavouring agents.

The catalyst used in the reaction is concentrated sulphuric acid.

Q56. Observe the structural formula and answer the following questions. Write the name of the given hydrocarbon. The given hydrocarbon is included in which type of hydrocarbon? What is the kind of compounds with the above characteristic structure called?

Answer

The given hydrocarbon is benzene.

The given hydrocarbon is included in cyclic hydrocarbon.

The compounds having this characteristic unit in their structure are called aromatic compounds.

Q57. Potassium permanganate is an oxidizing compound in regular use.

Potassium permanganate is an oxidizing compound in regular use- Right

Q58. Saturated carbon compounds : blue flame : : Unsaturated carbon compounds : _______

Saturated carbon compounds : blue flame : : Unsaturated carbon compounds : Yellow flame

Q59. Saturated hydrocarbon : Single bond : : Unsaturated hydrocarbon : _______

Saturated hydrocarbon : Single bond : : Unsaturated hydrocarbon : Double and/or triple bond

Q60. Solid : iodine : : _______ : bromine

Solid : iodine : : liquid : bromine

Q61. Substances that can give oxygen to other substances are called reductant.

Answer

The statement is Wrong.

Explanation:

Oxidising agents, not reductants, provide oxygen. A reductant provides electrons to another chemical, reducing it while oxidising the reductant.

Q62. The bond between two oxygen atoms is _______ bond.

The bond between two oxygen atoms is double bond .

Q63. The general molecular formula for the homologous series of alkynes is _______.

The general molecular formula for the homologous series of alkynes is `underline("C"_"n""H"_("2n" - 2))`.

Q64. The molecular masses of a carbon compound spread over a range of _______.

The molecular masses of a carbon compound spread over a range of 1012.

Q65. The number of electrons in the valence shell of a carbon atom is 4.

The number of electrons in the valence shell of a carbon atom is 4- Right

Q66. The phenomenon in which compounds having different structural formulae have the same molecular formula is called _______.

The phenomenon in which compounds having different structural formulae have the same molecular formula is called structural isomerism.

Q67. The unsaturated hydrocarbons containing a carbon-carbon double bond are called _______.

The unsaturated hydrocarbons containing a carbon-carbon double bond are called Alkenes.

Q68. There are different general molecular formula for all members of the homologous series.

There are different general molecular formula for all members of the homologous series- Wrong

Q69. Two carbon atoms can always form one or two covalent bonds.

This statement is Wrong.

Q70. What are catalysts?

Catalyst is a substance which increases the rate of a reaction without causing any disturbance to it.

Q71. What is an oxidising agent?

An oxidising agent is a reactant which readily transfers oxygen atoms to another substance by reducing itself in the process.

Q72. While going in an increasing order there is a rise in the molecular mass of the consecutive members of the homologous series by _______.

While going in an increasing order there is a rise in the molecular mass of the consecutive members of the homologous series by 14 u.

Q73. Write a short note. Aromatic hydrocarbons

Answer

Diagram: Refer textbook

Q74. Write a short note. Catenation power

Answer

The unique property of carbon atom to form covalent bonds with other carbon atoms giving rise to extremely big molecules is called catenation power.

The covalent bond between two carbon atoms is strong and stable.

This is the reason carbon is bestowed with catenation power.

Due to catenation power, carbon can form a large number of compounds containing open chains or closed chains of carbon atoms.

Q75. Write a short note. Characteristics of carbon

Answer

Catenation power: Carbon has a unique ability to form strong covalent bonds with other carbon atoms; this results in the formation of big molecules. This property of carbon is called catenation power.

Multiple bond formation: Two carbon atoms can be bonded together by one, two or three covalent bonds. These are called a single bond, double bond, and triple bond respectively. Thus, carbon atom has the ability to form multiple bonds as well as single bonds.

Tetravalency: Being tetravalent one carbon atom can form bonds with four other atoms (carbon or any other). This results in formation of many compounds.

Isomerism: One more characteristic of carbon, which is responsible for large number of carbon compounds is isomerism.

Q76. Write a short note. Functional groups in carbon compounds

Answer

Many more types of carbon compounds are formed by formation of bonds of carbon with other elements such as halogens, oxygen, nitrogen, sulphur.

The atoms of these elements (hetero atoms) substitute one or more hydrogen atoms in the hydrocarbon chain and thereby the tetravalency of carbon is satisfied.

The compound acquire specific chemical properties due to these heteroatoms or the groups of atoms that contain heteroatoms, irrespective of the length and nature of the carbon chain in that compound.

Therefore, these hetero atoms or the groups of atoms containing hetero atoms are called functional groups.

E.g. In CH3 – OH, –OH (alcohol) is the functional group-containing heteroatom ‘oxygen’.

Q77. Write a short note. Homologous series

Answer

The series of carbon compounds formed by joining the same functional group in the place of a particular hydrogen atom on the carbon chains having sequentially increasing length is called homologous series.

There are different homologous series in accordance with the functional group. For example, homologous series of alcohols, homologous series of carboxylic acids, homologous series of aldehydes, etc.

All the members of the homologous series are homologues of each other and they can be represented by the same general molecular formula.

Physical properties generally show a gradual change with the increase in molecular mass in the series whereas chemical properties of the members of the series show similarity because of the presence of the same functional group in them.

Q78. Write an Explanation. Alkane

Answer

The saturated hydrocarbons containing only single bonds between carbon atoms are called alkanes.

Q79. Write an Explanation. Alkene

Answer

An alkene is an unsaturated hydrocarbon that contains at least one carbon-carbon double bond.

Q80. Write an Explanation. Alkyne

Answer

An alkyne is a type of unsaturated hydrocarbon characterized by the presence of at least one carbon-carbon triple bond.

Q81. Write answer as directed. What is meant by vinegar and gashol? What are their uses?

Answer

Vinegar is the type of liquid which consist of acetic acid ( Ethanoic acid ). It is basically produced by the process of fermentation of ethanol through ethanoic acid in the presence of bacteria.

Reaction involved in the formation of Vinegar:

CH₃CH₂OH + O₂ → CH₃COOH + H₂O

Fermentation is the process of converting sugar into alcohol. But if the cork of the bottle open for sometimes then there is a second type of fermentation happened. In this process, alcohol is changes into acetic acid, so the main compound which formed is vinegar.

Uses of Vinegar are:

It is used in the preparation of the food.

It is used in pickling.

It is used as folk medicine material.

It is used as a household cleaning agent

Gasohol is a mixture of 90% gasoline and 10% of anhydrous Alcohol (Ethyl Alcohol). It is commonly known as alternative fuel or motor fuel.

Benefits of gasohol are:-

It is cheaper.

It is eco-friendly.

It has higher performance.

It is used as a cleaner for the environment.

It doesn't freeze in typical conditions.

Uses of gasohol are:

It is used in a fuel or petroleum Industry

It is used in an automobiles industry

It is used as common gasoline or hydrous around the world.

It is used as a flexible fuel vehicle, because it do not freeze in typical conditions.

Q82. Write scientific reason. Benzene compounds are called aromatic compounds.

Answer

Benzene compounds are cyclic unsaturated hydrocarbons having structure similar to benzene.

There are three alternate double bonds in the six-membered ring structure of benzene.

Compounds having this characteristic unit in their structures are called aromatic compounds.

Hence, benzene compounds are called aromatic compounds.

Q83. Write scientific reason. Carbon has the property of forming many compounds.

Answer

Carbon is a tetravalent atom with the property of catenation. Thus, it forms compounds in which the carbon atoms are arranged in the form of straight chains, branched chains or rings.

It can form single and multiple covalent bonds with other carbon atoms.

Carbon is tetravalent. Thus, it can form four covalent bonds with carbon or other elements like oxygen, nitrogen, sulphur, halogens and phosphorus.

One more characteristics of carbon, which is responsible for large number of carbon compounds is isomerism.

Hence, carbon has the property of forming many compounds.

Q84. Write scientific reason. Ethylene is an unsaturated hydrocarbon.

Answer

Hydrocarbons containing at least one carbon-carbon double or triple bond are called unsaturated hydrocarbons.

The structure of ethylene is CH2 = CH2. It has a double bond and hence, it is an unsaturated hydrocarbon.

Q85. Write scientific reason. The color of iodine disappears in the reaction between vegetable oil and tincture iodine.

Answer

Vegetable oils are unsaturated fatty acids.

They contain carbon-carbon multiple bonds and thus, undergo addition reaction with iodine.

Hence, the color of iodine disappears in the reaction between vegetable oil and tincture iodine.

Q86. Write scientific reason. The flame appears yellow in the ignition of naphthalene.

Answer

Naphthalene is an unsaturated hydrocarbon.

Unsaturated hydrocarbons burns with a yellow flame and releases black soot/smoke.

Hence, the flame appears yellow in the ignition of naphthalene.

Q87. Write scientific reason. Vegetable ghee is formed from the hydrogenation of vegetable oil in presence of nickel catalyst.

Answer

Vegetable oil contains carbon-carbon multiple bonds while vanaspati ghee contains carbon-carbon single bonds. So, vegetable oil is an unsatured compound while vanaspati ghee is a saturated compound.

An unsaturated compound undergoes addition reaction with hydrogen in presence of nickel catalyst to form a saturated compound. This reaction is called hydrogenation.

Hence, vanaspati ghee is formed from the hydrogenation of vegetable oil in presence of nickel catalyst.

Q88. Write the answers to the questions by observing the following figure. Write the chemical reaction shown in the figure above in the form of a balanced equation. Write the name of the gas coming out of the large test tube in the above chemical reaction. Why do small bubbles appear in the small test tube? What is the change in colour of lime water?

Answer

Balanced equation of the reaction between acetic acid and sodium carbonate is as follows:

\[\ce{\underset{\text{Acetic acid}}{2CH3COOH_{(aq)}} + \underset{\text{carbonate}}{\underset{\text{Sodium}}{Na2CO_{3(s)}}} -> \underset{\text{ethanoate}}{\underset{\text{Sodium}}{2CH3COONa_{(aq)}}} + \underset{\text{Water}}{H2O_{(l)}} + \underset{\text{Carbon dioxide}}{CO2\uparrow}}\]

The gas formed in the large test tube is carbon dioxide (CO2) gas.

The carbon dioxide gas produced in big test tube passes through bent gas delivery tube to the small test tube containing lime water. Hence, bubbles are seen in the small test tube.

Lime water turns milky.

Q89. Write the characteristics of ethanoic acid.

Answer

Ethanoic acid is a colourless liquid at ordinary temperature.

Its boiling point is 118 °C.

Melting point of pure ethanoic acid is 17 °C.

Its aqueous solution is acidic in nature and hence, turns blue litmus red.

Q90. Write the characteristics of ethanol.

Answer

It is colourless liquid at room temperature and

Its boiling point is 78 °C.

It is soluble in water in all proportions.

Its aqueous solution is neutral.

Q91. Write the molecular formula of the given compound. Acetic acid

Answer

Acetic acid- CH3COOH or C2H4O2

Q92. Write the molecular formula of the given compound. Acetone

Answer

Acetone- C3H6O

Q93. Write the molecular formula of the given compound. Acetylene

Answer

Acetylene- C2H2

Q94. Write the molecular formula of the given compound. Benzene

Answer

Benzene- C6H6

Q95. Write the molecular formula of the given compound. Ethanoic acid

Answer

Ethanoic acid- CH3COOH or C2H4O2

Q96. Write the molecular formula of the given compound. Ethanol

Answer

Ethanol- C2H5OH or C2H6O

Q97. Write the molecular formula of the given compound. Ethyl alcohol

Answer

Ethyl alcohol- C2H5OH or C2H6O

Q98. Write the molecular formula of the given compound. Ethyl ethanoate

Answer

Ethyl ethanoate- C4H8O2

Q99. Write the molecular formula of the given compound. Ethylene

Answer

Ethylene- C2H4

Q100. Write the molecular formula of the given compound. Isobutane

Answer

Isobutane- C4H10

Q101. Write the molecular formula of the given compound. Oleic acid

Answer

Oleic acid- C17H33COOH or C18H34O2

Q102. Write the molecular formula of the given compound. Palmitic acid

Answer

Palmitic acid- C15H31COOH or C16H32O2

Q103. Write the molecular formula of the given compound. Propene

Answer

Propene- C3H6

Q104. Write the molecular formula of the given compound. Propylene

Answer

Propylene- C3H6

Q105. Write the molecular formula of the given compound. Sodium ethanoate

Answer

Sodium ethanoate- C2H3O2Na

Q106. Write the molecular formula of the given compound. Sodium ethoxide

Answer

Sodium ethoxide- C2H5ONa

Q107. Write the molecular formula of the given compound. Stearic acid

Answer

Stearic acid- C17H35COOH or C18H36O2

Q108. Complete the following activity. Write the names of the hydrocarbons for the following structural formula. (isobutylene, cyclohexane, propene, cyclohexene, cyclopentane, benzene, propyne, isobutane, propane) \[\begin{array}{cc}\phantom{......}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{..}\\ \phantom{.....}|\phantom{....}|\phantom{....}|\\ \ce{H - C - C = C}\\\phantom{.....}|\phantom{.........}|\\ \phantom{.....}\ce{H}\phantom{........}\ce{H}\end{array}\]

Answer

\[\begin{array}{cc}\phantom{......}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{..}\\
\phantom{.....}|\phantom{....}|\phantom{....}|\\
\ce{H - C - C = C}\\\phantom{.....}|\phantom{.........}|\\
\phantom{.....}\ce{H}\phantom{........}\ce{H}\end{array}\]		 Propene

Q109. Complete the following activity. Write the names of the hydrocarbons for the following structural formula. (isobutylene, cyclohexane, propene, cyclohexene, cyclopentane, benzene, propyne, isobutane, propane) \[\begin{array}{cc}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\\ |\phantom{....}|\phantom{....}|\\\ce{H - C - C - C - H}\\ |\phantom{....}|\phantom{....}|\\\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H} \end{array}\]

Answer

\[\begin{array}{cc}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\\
|\phantom{....}|\phantom{....}|\\\ce{H - C - C - C - H}\\
|\phantom{....}|\phantom{....}|\\\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}
\end{array}\]		 Propane

Q110. Complete the following activity. Write the names of the hydrocarbons for the following structural formula. (isobutylene, cyclohexane, propene, cyclohexene, cyclopentane, benzene, propyne, isobutane, propane) \[\begin{array}{cc} \phantom{.........}\ce{H}\\ \phantom{.........}|\\ \ce{H - C ≡ C - C - H}\\ \phantom{.........}|\\ \phantom{.........}\ce{H} \end{array}\]

Answer

\[\begin{array}{cc}
\phantom{.........}\ce{H}\\
\phantom{.........}|\\
\ce{H - C ≡ C - C - H}\\
\phantom{.........}|\\
\phantom{.........}\ce{H}
\end{array}\]		 Propyne

Q111. Complete the following activity. Write the names of the hydrocarbons for the following structural formula. (isobutylene, cyclohexane, propene, cyclohexene, cyclopentane, benzene, propyne, isobutane, propane) \[\begin{array}{cc} \phantom{..}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\\ \phantom{..}|\phantom{....}|\phantom{....}|\\ \ce{H - C - C- C- H}\\ \phantom{.}|\phantom{....}|\phantom{....}|\\ \ce{H - C - H}\\ |\\\ce{H}\end{array}\]

Answer

\[\begin{array}{cc}
\phantom{..}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\\
\phantom{..}|\phantom{....}|\phantom{....}|\\
\ce{H - C - C- C- H}\\
\phantom{.}|\phantom{....}|\phantom{....}|\\
\ce{H - C - H}\\
|\\\ce{H}\end{array}\]		 Isobutane

Q112. Complete the following activity. Write the names of the hydrocarbons for the following structural formula. (isobutylene, cyclohexane, propene, cyclohexene, cyclopentane, benzene, propyne, isobutane, propane)

Answer

Diagram: Refer textbook

Q113. Your body is made up of carbon.

Your body is made up of carbon- Right

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