Carbon And Compound | Chapter 4 Notes Questions 2024

Last updated on July 14th, 2024 at 05:11 pm

Carbon And Compounds Notes

Below are some of the very important NCERT Class 10 Science chapter 4 carbon and compounds notes Questions with Answers. These Class 10 carbon and compounds notes have been prepared by expert teachers and subject experts based on the latest syllabus and pattern of term 2. Questions with Answers to help students understand the concept.

These Questions for Class 10 Science carbon and compounds notes are very important for the latest CBSE term 2 pattern. These class 10 notes and Q and A are very important for students who want to score high in CBSE Board.

We have put together these NCERT  Questions of Class 10 Science carbon and compounds notes questions with answers for practice on a regular basis to score high in exams. Refer to these Questions with Answers here along with a detailed explanation.

Carbon is the third most important element after oxygen and hydrogen, for the existence of life on the Earth. The Earth crust has only 0.02% carbon which is present in the form of minerals (like carbonates, hydrogen-carbonate, coal, petroleum, etc.) and the atmosphere has 0.03% of carbon dioxide.

Fuels (like wood, kerosene, coal, LPG, CNG, petrol, etc.) clothing material (like cotton, nylon, polyester, etc.), paper, rubber, plastics, leather, drugs and dyes are all made up of carbon.

carbon and compounds notes

Covalent Bonding in Carbon Compounds

The bonds which are formed by the sharing of an electron pair between the atoms (either same or different atoms) are known as covalent bonds.

Atomic number of carbon (C) is 6.

So, its electronic configuration = k 2, L 4

Thus, there are 4 electrons in its outermost shell and its octet can be completed by the following two ways

  • It could gain 4 electrons and form C4- anion. But for a  nucleus having 6 protons, it would be difficult to hold on 10 electrons; i.e. 4 extra electrons. 
  • It could lose 4 electrons form C4+ cation. But a large amount of energy is required to remove 4 electrons leaving behind a carbon cation with 6 protons in its nucleus holding on just two electrons together, which is not possible.

In order to overcome this problem, carbon shares its valence electrons with other atoms of carbon or with atoms of other elements.

These shared electrons belong to the outermost shells of both atoms and in this way; both atoms attain the nearest noble gas configuration. This type of bonding is called covalent bonding.

Compounds having covalent bonds are called covalent compounds, these are generally poor conductors of electricity.

Examples of Covalent Bonding

Some example depicting of     bonding are as follows:

1. Formation of Methane (CH4)

In the formation of a methane molecule, one carbon atom shares its 4 electrons with four hydrogen atoms (one electron of each hydrogen atom). It shows carbon is tetravalent because it possesses 4 valence electrons and hydrogen is monovalent because it has only 1 valence electron.

carbon and compounds notes

2. Formation of Water Molecule (H 20)

Atomic number of O = 8  

Electronic configuration = K2, L6

Atomic number of H = 1

Electronic configuration = K1

To attain the stable electronic configuration of the nearest noble gas, hydrogen needs 1 electron and oxygen needs 2 electrons. So, two hydrogen atoms share an electron pair with the oxygen atom such that hydrogen acquires a duplet configuration and oxygen an octet, resulting in the formation of two single covalent bonds.

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Properties of Covalent Compounds

The compounds containing covalent bonds are called covalent compounds. They have following properties i.e.

  • Covalent compounds have low melting and boiling points due to small intermolecular forces of attraction between the atoms.
  • Covalent compounds are generally poor conductors of  electricity. This is because the electrons are shared between atoms and no charged particles are formed in these compounds.
  • Covalent compounds are generally volatile in nature.

Allotropes of Carbon

Allotropy is the property by virtue of which an element exists in more than one form and each form has different physical properties but identical chemical properties. These cli(lörent forms are called allotropes. 

Carbon exists in dillörent allotropic forms; some of them are diamond? graphite and fullerene.

Diamond is a colorless transparent substance and very hard whereas graphite is an opaque substance which has a smooth surface and is slippery to touch.

Fullerenes are recently discovered allotrope carbon which were prepared for the first time by Kroto, Smalley and Robert Curt by the action of laser on the vapors of graphite.

Versatile Nature of Carbon

Main factors that are responsible for the formation of large number of carbon compound are:

(i) Catenation. The property of self linking of elements, mainly C-atoms through covalent bonds to form long, straight or branched chains and rings of different sizes is called catenation. Carbon shows maximum catenation in the periodic table due to its small size and strong C —– C bond 

(ii) Tetravalency of carbon. The valency of carbon is four, i.e. it is capable of bonding or pairing with four other carbon atoms or with the atoms of some other monovalent elements like hydrogen, halogen (chlorine, bromine), etc.

(iii) Tendency to form multiple bonds. Carbon has a strong tendency to form multiple bonds due to its small size. It shares more than one electron pair with its own atoms or with the atoms of elements like oxygen, nitrogen, sulfur, etc.

Organic Compounds

The compounds of carbon except its oxides, carbonates and hydrogen carbonate salts, are known as organic compounds. In 1828, German chemist Friedrich Wohler accidently prepared urea from ammonium cyanate when he was trying to prepare ammonium cyanate by heating ammonium sulphate and potassium cyanate. Thus, synthesis of urea discarded the vital force theory. 

Hydrocarbons

Organic compounds made up of carbon and hydrogen are called hydrocarbons. These are of two types, i.e.

1. Aliphatic Saturated Hydrocarbons

Saturated aliphatic hydrocarbons are called alkane or paraffin. All the carbon atoms in these are bonded through single bonds.

The general formula of these compounds is CnH2n+2 and stiflix  “-ane” are used in their nomenclature. e.g. CH4 (methane), C2H6 (ethane), etc.

2. Aliphatic Unsaturated Hydrocarbons

Those compounds in which at least one double or triple bond is present between two carbon atoms are called unsaturated hydrocarbons

Aliphatic unsaturated hydrocarbons are of two types:

(i) Alkene. Those hydrocarbons which must have at least one carbon-carbon care double called alkenes or olefins.

The general formula of compound is CnH2n, 

e.g. C2H4 (ethene).

(ii) Alkyne. Those hydrocarbons which must have at least one carbon-carbon triple bond are called alkynes. 

The general common formula of these compounds is CnH2n-2  e.g. C2H2 (ethyne).

Structure of Saturated and Unsaturated Compounds

Steps to draw the structure of carbon compound are

Step l. First connect all the carbon atoms together with a single bond.

Step Il. After that use the hydrogen atoms to satisfy the remaining valencies of carbon (as carbon forms 4 bonds due to its 4 valency).

Step Ill. If the number of available H-atoms are less than what is required, satisfy the remaining valency by using double or triple bond.

1. Structure of Propane (C3H8)  

Same rules are followed here as in the case of Ethane. Here, the three carbon atoms are linked together with a single bond.

  C—C—C [ Step 1]

To satisfy the remaining valencies of carbon atoms, hydrogen  atoms are linked with them.

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2 Carbon atoms are bonded to 3 hydrogen atoms and 1 carbon atom is bonded to 2 hydrogen atoms. 

Electron dot structure of propane

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2. Structure of Ethene (C2H4)

Link the two carbon atoms by single bond.

C—C    [Step I] 

Link the four hydrogen atoms with carbon atoms to satisfy the unsatisfied valencies of carbon.

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But in this case, even after linking the available hydrogen atoms with carbon atoms, still one valency of each carbon remains unsatisfied.

To satisfy it, a double bond is used between the two carbon  atom.

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Now, all the four valencies of     are satisfied.

Electron dot structure of ethene

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3. Structure of Ethyne (C2H2)

Link the two carbon atoms by single bond.

    C—C                      [Step I]

Link the two hydrogen atoms with unsatisfied valencies of carbon.

     H—C—C—H                  [step II] 

But in this case even after linking the available hydrogen  atoms with carbon atoms, still two valencies of each carbon is unsatisfy. To satisfy it, a triple bond is used between the two carbon atoms.

        H—C=C—H                 [step III]

In ethyne, the two carbon atoms share three pairs of electrons among themselves to form a carbon-carbon triple bond.

Each carbon atom shares one electron with each hydrogen atom to form two carbon-hydrogen single bonds. 

Electron dot structure of ethyne

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4. Structure of Cyclic Compounds

In some compounds, carbon atoms are arranged in the form of rings. e.g. cyclohexane (C6H12 ) and benzene (C6H6 ).

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Isomerism

Organic compounds with the same molecular formula but different chemical and physical properties are called isomers. This phenomenon is called isomerism.

The difference in properties of these compounds is due to the difference in their structures. These compounds have identical molecular formulas but different structures. Hence, they are called structural isomers and the phenomenon is called structural isomerism.

e.g. Two structural isomers are possible for butane (C4H10)

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Functional Groups

Groups which combine with a carbon chain and decide its chemical properties are called functional groups.

e.g. — OH in R—OH will decide the chemical properties of this compound, thus it is a functional group.

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Homologous Series

A series of similarly constituted compounds in which the members present have the same functional group and similar chemical properties and any two successive members in a particular series differ in their molecular formula by a —CH2— unit, is called a homologous series,

e.g.  CH4, C2H6, C3-H8, C4H10 are the members of the alkane family.


Frequently Asked Questions

Short Answer Type Questions

1. What do you mean by covalent bonding?

Ans. Carbon shares it’s valence electrons with other atoms of carbon or with atoms of other elements in order to complete it’s octet, These shared electrons belong to the outermost shells of both at01ns and in this way, both atoms attain the nearest noble gas configuration. This type of bonding is called covalent bonding.

2. Explain the nature of the covalent bond using the bond formation in CH3Cl. (NCERT)

Ans. The bonds that are formed by sharing electrons are known as covalent bond. In covalent bonding, both atoms share the valence electrons, i.e. the shared electrons belong to the valence shells of both the atoms. CH3Cl is called chloromethane, which contains 1 carbon atom, 3 hydrogen atoms and I chlorine atom.

Electronic configuration of carbon, 6 = k 2, L 4

Electronic configuration of hydrogen, 1= k 1

K L M

Electronic configuration of chlorine,17= K 2, L 8, M 7

Carbon atoms have four outermost electrons, each hydrogen atom has one electron and chlorine has seven outermost electrons. Carbon shares its four outermost electrons with 3 hydrogen atoms and I chlorine atom to form CH3Cl as follows:

carbon and compounds notes

3. What would be the electron dot structure of carbon dioxide which has molecular formula C02 ? (NCERT)

Ans. Atomic  of C = 6

Electronic configuration =  K 2, L 4

Atomic number of O = S

Electronic configuration =  K2, L 6

To attain the stable electronic configuration, carbon needs 4 electrons, while oxygen needs 2 electrons. So, in CO2, each oxygen atom shares two electrons from carbon. Thus, oxygen and carbon both complete their octet.

carbon and compounds notes

4. (i) Explain the formation of calcium chloride with the help of electron dot structure. 

(Atomic numbers of Ca = 20; Cl = 17)

Ans. (i) The formation of calcium chloride with the help of electron dot structure.

carbon and compounds notes

Two valence electrons of calcium attack the valency of two chlorine to attain the noble gas configuration.

(ii) Why do ionic compounds not conduct electricity in solid state but conduct electricity in molten and aqueous state?

Ans. (ii) Ionic compounds do not conduct electricity in solid state but conduct electricity in molten and aqueous state because in solid state, there is no free ion to move and pass electricity. Whereas in the molten and aqueous state, there are free ions to move and pass electricity.

5. Carbon, a group (14) element in the periodic table, is known to form compounds with many elements. Write an example of a compound formed with

(i) chlorine (group 17 of periodic table)

(ii) oxygen (group 16 of periodic table) (NCERT Exemplar)

Ans. (i) Electronic configuration of carbon, C(6) is  K 2, L  4.

Electronic configuration of chlorine, Cl (17) is K 2,  L 8, M 7.

To attain the electronic configuration of the nearest noble gas, carbon needs 4 electrons and chlorine needs 1 electron.

So, with chlorine, carbon forms carbon tetrachloride. Electron dot structure and structural formula ofCC14 is as follows

carbon and compounds notes

(ii) Electronic configuration of oxygen, O(8) is K 2, L 6.

With oxygen, carbon forms carbon dioxide. To attain the electronic configuration of the nearest noble gas, carbon needs 4 electrons and oxygen needs 2 electrons.

Therefore, in CO2, each oxygen atom shares 2 electrons with carbon. Electronic configuration of carbon (6) is K 2, L 4

The electron dot structure and structural formula of CO2

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6. Why are covalent compounds volatile in nature with low boiling and low melting point?

Ans. Covalent compounds have low melting and boiling points due to small intermolecular forces of attraction between the atoms.

 7. State the valency of each carbon atom in

    (i) an alkane and    (ii) an alkyne

Ans. (i) Valency of each carbon atom in an alkane is four.

(ii) Valency of each carbon atom in an alkyne is four.

8. Covalent compounds are generally poor conductors of electricity. Why? (CBSE 2020) 

Ans. 8. Covalent compounds are poor conductors of electricity because covalent bonds are formed by sharing of electrons between atoms.

So, they don’t have a free electron that is required for electricity transfer (electricity is the flow of free electrons).

Thus, they are bad conductors. 

9. Diamond is a poor conductor of electricity while graphite is a good conductor. Assign reason.

Ans. In the structure of diamond, all the four valence electrons of carbon are involved in the formation of covalent bonds.

Thus, no free electrons are available.

Whereas, in the structure of graphite, three electrons in the valence shell of carbon are involved in covalent bond formation and the fourth electron is free to move. 

Therefore, graphite is a good conductor of electricity.

10. Why do diamonds have a high melting point?

Ans. Diamond has a giant structure that consists of carbon atoms in which each carbon atom is bonded to four other carbon atoms forming a rigid three-dimensional network structure,  which is responsible for its hardness. 

So, a lot of energy is required to break the network of strong covalent bonds. That’s why it has a high melting point.

11. What are the main factors that enable carbon to form a large number of compounds?

Ans. The main factors that enables carbon to form large number of compounds are

(i) Catenation. The tendency of carbon to form chains Of identical atoms is known as catenation. Carbon fonns long chains by combining with other carbon atoms through covalent bonds,

(ii) Tetravalency. It has 4 valence electrons, so it can form 4 covalent bonds with four different atoms, or two double bonds or a single and a triple bond with other  This tendency helps carbon to [orm a large number 01 compounds.

(iij) Tetravalency. Carbon forms  strong bonds with most of other elements like H, O, N, S, Cl etc. due to it’s small size which helps it to attract more electrons 

12. Select saturated hydrocarbons from the following:

C3H6, C5 H10, C4 H10, C2H4, C6H14

Ans. The hydrocarbons in which all the carbon atoms are connected by only single bonds are called saturated hydrocarbons or alkanes are paraffins. 

The general formula of these compounds is CnH2n+2

where n=  number of carbon atoms in one molecule of a hydrocarbon.

Amongst the given compound, only C4H10 and C6H14 belong to the formula of CnH2n+2. Therefore, C4H10 and C6H14 are saturated hydrocarbons.

13. What will be the formula and electron dot structure of cyclopentane?    (NCERT)

Ans. 13. General formula of cycloalkane =  CnH2n

In cyclopentane, n=5

Therefore Formula of cyclopentane, C5H5×2=C5H10

carbon and compounds notes

14. Answer the following

(i) Carbon is a versatile element. Give a reason.

(ii) Explain the structural difference between saturated and unsaturated hydrocarbons with two examples each.

(iii) What is a functional group? Write examples of four different functional groups.

Ans. (i) Carbon is a versatile element because of its properties. It shows the property of catenation due to which it forms a large number of compounds. Carbon is tetravalent. Due to this, it forms covalent compounds only.

(ii) Saturated hydrocarbons contain carbon-carbon single bonds. e.g. Methane (CH4), ethane (C2H6). Unsaturated hydrocarbons contain at least one carbon-carbon double or triple bond. e.g. Propene (C3H6), butyne (C4H6). 

(iii) Functional group is an atom or group of atoms joined in  a specific manner which is responsible for the characteristics and chemical properties of the organic  compounds.

Examples are alcohols ( —OH) , aldehyde group  (— CHO), carboxylic group (—COOH),  ketone (—CO)  etc.

15. Write the molecular formula of the following con)pounds and draw their electron dot structures

(i) Ethane    (ii) Ethene    (iii) Ethyne

Ans.

carbon and compounds notes

16, What is meant by isomers? Draw the structures of two isomers of butane, C4-H10. Explain why we cannot have isomers of the first three members of the alkane series?

Ans. Isomers are those molecules which have the same molecular formula but different structural formulas, i.e. show different properties.

carbon and compounds notes

The first three members of alkane series are:

(i) CH4 (methane)

(ii) C2H6 (ethane)

(iii) C3H8 (propane) 

In the above members of the alkane series, it is not possible to have different arrangements of carbon atoms, because branching is not possible from either first or last carbon. Thus, we cannot have isomers of the first three members of the alkane series.

17. Draw the possible isomers of the compound with molecular formula C3H6O and also give their  electron clot structures. (NCERT Exemplar)

18. What is meant by the functional group in carbon compounds? Write in tabular form the structural formula and the functional group present in the following compounds:      (i) Ethanol    (ii) Ethanoic acid

Ans. 17 and 18

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18. What is meant by the functional group in carbon compounds? Write in tabular form the structural formula and the functional group present in the following compounds:      (i) Ethanol    (ii) Ethanoic acid

Ans. An atom or a group of atoms present in a molecule which largely determines its chemical properties is called a functional group.

19. Describe the applications of homologous series.

Ans. Application of homologous series are as follows

All Inelübers of homologous series show similar chemical properties and are generally prepared through one common method e.g. all alkenes are prepared by (Hydration of con-esponding alcohols.

The physical properties of the members change gradually,

i.e. show gradation in properties as the number of carbon atoms per molecule increases.

20. Why is the homologous series of carbon compounds so called? Write the chemical formula of two consecutive members of any homologous series and state the part of these compounds that determines  their

 (i) physical and (ii) chemical 

Ans. A homologous series is the family of organic compounds having the same functional group, similar chemical properties but the successive (adjacent) members of the series differ by a CH2 unit or 14 mass units.

Consecutive members of the homologous series of alcohols are

CH30H, C2H5OH. They differ by  —CH2 units.

The physical properties are determined by alkyl group/ hydrocarbon part/part other than the functional group. The chemical properties are determined by functional    group such as — OH group.

21. Write the next higher order homologous 

    CH2O and C2H5COOH.

Ans. Add —CH2 group to each compound to obtain the next homologous.

    Compounds    Homologue compounds

CH20    C2H40, C3H60, C4H80…

C2H2    C3H4, C4H6, C5H8…

C2H5COOH    C3H7COOH, C4H9COOEL

C5H11COOH

Long Answer Type Questions

22. State the reason why carbon can neither form C+ cations nor C4- anions, but forms covalent compounds. Also state reasons to explain why covalent compounds 

(i) Are ‘bad conductors of electricity?     

(ii) Have a low melting and boiling point?

Ans. Atomic number of carbon is six. This means that it has four electrons in its outermost shell and it needs four more electrons to attain noble gas electronic configuration. It does not form C4+ cation, as the removal of four valence electrons will require a huge amount of energy.

The cation formed will have six protons and two electrons. This makes it highly unstable. Carbon is unable to form C4 -anion as its nucleus with six protons will not be able to hold ten electrons due to its small size. 

Thus, carbon achieves noble gas electronic configuration by sharing its four electrons either with same or different other atoms,

i.e. it forms covalent compounds.

(i) Covalent compounds do not have free ions, due to this they are bad conductors of electricity in solid, molten or aqueous state.

(ii) Covalent compounds are formed by covalent bonds and it has been found that the intermolecular force of attraction in covalent compounds are weak,

Thus, a low amount of energy is required to break these forces of attraction. Hence, their melting and boiling points are quite low.

23. Explain the formation of oxygen (O2) molecules and sulfur (S 8) molecules. 

Ans. Formation of Oxygen Molecule (O2)

The atomic number of oxygen is 8 and electronic configuration is 2, 6, i.e. has 6 electrons in its outermost shell. So, it requires 2 electrons to complete its octet for attaining noble gas configuration. 

Hence, it shares two electrons with another atom of oxygen to make a molecule of oxygen.

By doing so, both the atoms of oxygen get 8 electrons in their outermost shell. Thus, a double bond is formed between two oxygen atoms which consists of four electrons.

carbon and compounds notes

Formation of Sulphur Molecule ( S8 )

The atomic number of sulphur is 16 and electronic configuration is 2, 8, 6. It also has 6 electrons in it’s outermost shell and requires 2 electrons to complete it’s octet state. So, each sulphur atom shares two electrons, 1 with each adjoining sulphur atom by single covalent bonds and thus, complete its octet.

carbon and compounds notes

Eight sulphur atoms form a puckered ring or crown structure to form an eight atom molecule.

24. What are covalent compounds? Why are they  different from ionic compounds? List their three characteristics. 

Ans. Covalent compounds are those compounds which are formed by sharing of valence electrons between the atoms. e.g. Hydrogen molecule is formed by mutual sharing of electrons between two hydrogen atoms.

They are different from ionic compounds as ionic compounds are formed by the complete transfer of electrons from one atom to another, e.g. NaCl is formed when one valence electron of sodium gets completely transferred to the outer shell of the chlorine atom. The characteristic properties of covalent compounds are

(i) They are generally insoluble or less soluble in water but soluble in organic solvents.

(ii) They have low melting and boiling points.

(iii) They do not conduct electricity as they do not contain ions.

(iv) They are volatile in nature.

25. Why are organic compounds called hydrocarbons? Write the general formula for homologous series of alkanes, alkenes and alkynes and also draw the structure of the first member of each series.  

Ans. Organic compounds are called as hydrocarbons because they are made up of only the elements-carbon (C) and hydrogen H) 

General formula for the homologous series of alkanes is CnH2n+ 2  which are classified as saturated hydrocarbons or alkanes.

General formula for the homologous series of alkanes is CnH2n. which are classified in the category of unsaturated hydrocarbons. They are known as alkenes or olefins. First a member of the alkene family is “ethane”.

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General formula for the homologous series of alkynes is CnH2n-2 and they are also in the category of unsaturated hydrocarbons. First rncmbcr of the family is “ethyne 

  H—C=C—H

 26. Identify the functional group present in the following compounds  

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carbon and compounds notes

Ans.

carbon and compounds notes

Case Based Questions

27. Read the following and answer the questions from (i) to (v) given below

Compounds which contain only carbon and hydrogen are called hydrocarbon. Among these, the compounds containing all single covalent bonds are called saturated hydrocarbons while the compounds containing at least one double or triple bond are called unsaturated hydrocarbons. 

Saturated hydrocarbons after combustion give a clean flame while unsaturated hydrocarbons given a yellow sooty flame. Unsaturated hydrocarbons are more reactive than saturated hydrocarbons.  

Unsaturated hydrocarbons add hydrogen in the presence of catalysts such as palladium or nickel to give saturated hydrocarbons. 

Study the table related to three hydrocarbons ### A, B, C and  answer the questions that follows

(i) What is the name of compound B?

(ii) Write two differences between saturated and unsaturated hydrocarbons.  

(iii) In unsaturated compounds, what is the minimum number of carbon atoms and why?

(iv) Among compounds A, B and C, which of the following is saturated hydrocarbon?

(v) Compound C belongs to which category of hydrocarbon and what is it’s general formula ?

Ans.

(i) Compound B has molecular formula as C5H10 and contains 5 number of carbon atoms i.e.  n =  5 

It resembles the general formula of alkene which is C5H10.

So, the name of this compound is pent + ene = pentene. When 5 number of carbon atoms are present, it is named as “pent”

(ii) 

Saturated hydrocarbonsUnsaturated hydrocarbons
These hydrocarbons are linked by only single covalent bondThese hydrocarbons contains at least one double or triple bond along with single bonds. They are divided into two categories
– Alkenes or Olefins
– Alkynes
General formula of these compounds is CnH2n+ 2General formula of alkene is CnH2n and general formula of alkyne is CnH2n – 2

(iii) The minimum number of carbon atoms present in an unsaturated compound is two because formation of double or triple bonds is possible only between two carbon atoms.

(iv) The molecular formula of compound A is C3H8, i.e. contains three numbers of carbon atoms and resembles the general formula of alkanes which is Cn H2n+ 2.  So, A is a saturated hydrocarbon.

While the molecular formula of compounds B and C is C5HJ() and C4H6 which resembles the general formula of alkene and alkyne. So, B and C are unsaturated hydrocarbons.

(v) The molecular formula of compound C is C4H6 which resembles alkyne because there are four numbers of carbon atoms and 6HI-atoms, i.e. number of H-atoms are only increased by 2. So, the general formula of alkyne is CnH2n-2

28. Read the following and answer the questions from (i) to (v) given below

Organic compounds with the same molecular formula but different chemical and physical properties are called isomers. This phenomenon is called isomerism.

When the isomerism is due to difference in the arrangement of atoms within the molecule, without any reference to space, the phenomenon is called structural isomerism. 

In other words, structural isomers are compounds that have the same molecular formula but different structural formulas, i.e. they are different in the order in which different atoms are linked or they have different connectivities depending upon the order they are put together. 

In these compounds, carbon atoms can be linked together in the form of straight chains, branched chains or even rings.

(i) Name any set of compounds that have the same molecular formula but different structural formulas.

(ii) Which property of carbon leads to formation of branched chains P

(iii) How many isomers of pentane are possible?

(iv) Name two compounds that contains six carbon atoms and have cyclic structure.

(v) What is the minimum number of carbon atoms required to form an isomer?

29. Read the following and answer the questions from (i) to (v) given below

Hydrocarbons are the simplest organic compounds and are regarded as parent organic compounds. All other compounds are considered to be derived from them by the replacement of one or more hydrogen atoms by other atoms or groups of atoms.

Functional groups is an atom or group of atoms which makes a carbon compound (or organic compound)  reactive and decides it’s properties. 

A series of organic compounds having the same functional group with similar or almost identical chemical characteristics in which  all the members can be represented by the same general formula and two consecutive members of the series differ by —CH2 group in their molecular formula is called a homologous series.

carbon and compounds notes

(i) Which compounds belong to the same homologous series?

 (ii) What is the functional group of compound R ?

(iii) Compound T belongs to which homologous series ?

(iv) Among the P, S, T and U compounds which belong to the alkane series?

(v) With respect to Q, R, and U compounds, which one is an unsaturated hydrocarbon?

Ans. 28 and 29

Ans. 28 (i) Butane and iso-butane are the compounds that have sarne molecular formula but different structural formula.

CH3CH2CH2CH3    CH3CHCH3

Butane                                |

                                        CH3

                                     Iso- butane

(ii) Due to the catenation property of carbon, it forms long, straight or branched chains and rings of different sizes. 

carbon and compounds notes
carbon and compounds notes

Final Words

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