Class 10 Science Chapter 4 Important Questions Carbon And Its Compound

Class 10 Science Chapter 4 Important Questions Carbon and Its Compound

Class 10 Science Chapter 4 Important Questions Carbon and Its Compound

Class 10 Science Chapter 4 Important Questions Carbon and Its Compound, (Science) exams are Students are taught thru NCERT books in some of the state board and CBSE Schools. As the chapter involves an end, there is an exercise provided to assist students to prepare for evaluation. Students need to clear up those exercises very well because the questions inside the very last asked from those.

Sometimes, students get stuck inside the exercises and are not able to clear up all of the questions.  To assist students, solve all of the questions, and maintain their studies without a doubt, we have provided a step-by-step NCERT Important Questions for the students for all classes. These answers will similarly help students in scoring better marks with the assist of properly illustrated Notes as a way to similarly assist the students and answer the questions right.

Class 10 Science Chapter 4 Important Questions Carbon and Its Compound

 

Objective type questions

 

MCQS (1 Mark Each)

1. Which of the following is not observed in a homologous series?

(A) Change in chemical properties

(B) Difference in-CH2 and 14u molecular mass

(C) Gradation in physical properties

(D) Same functional group

Ans. Option (A) is correct.

2. Ethane, with the molecular formula C2H6 has:

(A) 6 covalent bonds

(B) 7 covalent bonds

(C) 8 covalent bonds

(D) 9 covalent bonds

Ans. Option (B) is correct.

3. Carbon forms four covalent bonds by sharing its four valence electrons with four univalent atoms, e.g., hydrogen. After the formation of four bonds, carbon attains the electronic configuration of

(A) helium

(B) neon

(C) argon

(D) krypton Explanation

Ans. Option (B) is correct.

4. The correct electron dot structure of a water molecule is:

(A) H-Ö H

(B) H: Ö- H

(C) H:O: H

(D) H:O: H

Ans. Option (C) is correct.

5. Which of the following statements are usually correct for carbon compounds?

(i) These are good conductors of electricity.

(ii) These are poor conductors of electricity.

(iii) These have strong forces of attraction between their molecules.

(iv) These do not have strong forces of attraction between their molecules.

(A) (i) and (iii)    (B) (ii) and (iii)     (C) (i) and (iv)      (D) (ii) and (iv) 

Ans. Option (D) is correct.

Explanation: The atomic number of carbons is 6. So, its electron configuration is 2, 4. Carbon having four valence electrons forms covalent compounds which show less intermolecular attractions and do not have any free electrons to transmit electric current. Therefore, these are poor conductors of electricity.

6. A molecule of ammonia (NH3) has:

(A) only single bonds

(B) only double bonds

(C) only triple bonds

(D) two double bonds and one single bond

Ans. Option (A) is correct.

Explanation: In ammonia covalent bond is present in which center nitrogen atom is bonded with three hydrogen atoms through single covalent bond.

7. Which of the following does not belong to the same homologous series?

(A) CH4 (B) C2H6 (C) C3H8 (D) C4H8

Ans. Option (D) is correct.

Explanation: A series of compounds in which the same functional group substitutes for hydrogen in a carbon chain is called as homologous series. The option (d) is alkene that follows the general formula CnH2n while others follow the general formula CnH2n+2

 

Assertion and Reason Based MCQS (1 Mark Each)

Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as:

(A) Both A and R are true, and R is the correct explanation of A.

(B) Both R are true, but R is NOT the correct explanation of A.

(C) A is true, but R is false.

(D) A is false and R is true.

2. Assertion (A): In a homologous series of alcohols, the formula for the second member is C2H5OH and the third member is C3H7OH.

Reason (R): The difference between the molecular masses of the two consecutive members of a homologous series is 144.

Ans. Option (C) is correct.

Explanation: In homologous series of alcohols, the formula for the second member is C2H5OH and the third member is C3H7OH. The difference between the molecular masses of the two consecutive members of a homologous series is 14u.

2. Assertion (A): Following are the members of a homologous series: CH3OH, CH3CH2OH, CH3CH2CH2OH

Reason (R): A series of compounds with same functional group but differing by- CH2 – unit is called a homologous series.

Ans. Option (A) is correct.

Explanation: Homologous series is a series of 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. For example, the series like methanol, ethanol, propanol and so on is a homologous series of alcohol.

3. Assertion (A): Following are the structural išomers of butane.

Diagram, schematicDescription automatically generated

Reason (R): Structural isomers have the same molecular formula, but they differ in their structures.

Ans. Option (A) is correct.

Explanation: Isomers are defined as those compounds that possess same molecular formula but different structural arrangement. Butane has the molecular formulae C4H10 Therefore, the structural isomers of butane will be n-butane and iso-butane.

4. Assertion (A): Third member of alkane is propane (C3H8)

Reason (R): It is obtained from general formula CnH2n+2

Ans. Option (A) is correct.

Explanation: C3H8 can be obtained from general formula, CnH2n+2. Where n = 3

5. Assertion (A): Carbon atoms have the ability to form four strong covalent bonds.

Reason (R): Carbon has the ability to make single, double and triple bonds with itself.

Ans. Option (B) is correct.

Explanation: Carbon contains four electrons in its outermost shell. Therefore, it can form four covalent bonds with other atoms or molecules to complete its octet and reach noble gas configuration. Also, carbon has the ability to make single, double and triple bonds with it.

6. Assertion (A): Most of the carbon compounds are good conductors of electricity.

Reason (R): They do not dissociate to form ions and remain as molecules.

Ans. Option (D) is correct.

Explanation: Carbon compounds are mainly poor conductors of electricity because there is no free electrons present to transmit electricity.

Case-based MCQS (1 Mark Each)

I. Read the passage and answer the given questions.

A homologous series is a series of organic compounds which belong to the same family (1.e. possess same functional group) and show similar chemical properties. The members of this series are called homologous and differ from each other by the number of CH2 units in the main carbon chain.

1. The chemical properties of which of the following compounds is similar to the butane?

(A) Butyne (B) Propene (C) Propyne (D) Pentane

Ans. Option (D) is correct.

Explanation: Methane, ethane, propane, butane, pentane etc. are all part of the alkane homologous series and have similar chemical properties.

2. The difference between two consecutive members in a homologous series in alkanes in terms of molecular mass and number of atoms of elements is:

(A) 14 amu and CH, respectively

(B) 12 amu and CH, respectively

(C) 14 amu and CH respectively

(D) 12 amu and CH, respectively

Ans. Option (A) is correct.

Explanation: Homologous series is a series of 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.

3. Which of the following is not the property of a homologous series?

(A) They show similar chemical properties.

(B) They differ by 14 units by mass.

(C) They all contain double bond

(D) They can be represented by a general formula.

Ans. Option (C) is correct.

Explanation: The characteristics homologous series are:

• They have same general formula.

• Successive compounds differ by -CH2 unit.

• Successive compounds have molecular mass difference of 14u.

• Molecular mass increases down the series. Therefore, members of homologous series show gradation in physical properties such as melting point and boiling points.

• Members of homologous series show similar chemical properties.

4. Which of the following represent the name and formula of the 2nd member of homologous series having general formula CnH2n=2?

(A) Methane CH4 (B) Ethane C2H6 (C) Ethene C2H4 (D) Ethyne C2H6

Ans. Option (B) is correct. A.

Explanation: Methane, ethane, propane, butane, etc. are all part of the alkane homologous series. The general formula of this series is CnH2n+2 Ethane (C2H6) is 2nd member as n = 2.

II. Read the given passage and answer the questions given below:

Carbon has the unique property to form bonds with other atoms of carbon.

1. Name the characteristic property of carbon as depicted in the fig.

(a) Catenation (B) Polymerisation (C) Isomerisation (D) None of the above.

Ans. Option (A) is correct.

Explanation: Carbon forms bond with other atoms of carbon. This property of carbon is known as catenation.

2. Carbon forms large number of compounds due to:

(A) Catenation only

(B) Tetravalency only

(C) Both catenation and tetravalency

(D) None of the above

Ans. Option (C) is correct.

Explanation: Carbon forms large number of compounds due to the following:

(i) Catenation: Carbon forms bond wit h other atoms of carbon.

(ii) Tetravalency: Carbon share four electrons with other atoms.

3. Carbon is:

(A) Divalent

(B) Monovalent

(C) Tetravalent

(D) Trivalent

Ans. Option (C) is correct.

Explanation:

  • Carbon has valency of four.
  • It is capable of bonding with four other atoms of carbon or atoms of some other monovalent element.
  • Carbon can form bond with Oxygen, Hydrogen, Nitrogen, Sulphur, Chlorine and many other elements giving rise to compounds with specific properties.

4. Write the name and structure of a saturated compound in which 6 carbon atoms are arranged in a ring.

(A) Hexane (B) Cyclohexane (C) Pentane (D) Cyclopentane

Ans. Option (B) is correct.

Explanation:

  • Cyclohexane is the carbon compounds in which carbon atoms are arranged in the form of a ring.
  • It is a cyclic carbon compound.
  • Its structure is:

III. Read the passage and answer the questions given below:

Homologous series is a series of compounds with similar chemical properties and same functional group differing from the successive member by CH2 unit. Carbon chains of varying length have been observed in organic compounds having the same general formula. Such organic compounds that vary from one another by a repeating unit and have the same general formula form a series of compounds. Alkanes with general formula CnH2n+2, alkenes with general formula CnH2n and alkynes with general formula CnH2n-2 the most basic homologous series in organic chemistry.

All the members belonging to this series have the same functional groups. They have similar physical properties and follow a fixed gradation with increasing mass. This series has enabled scientists to study different organic compounds systematically. They can predict the properties of organic compounds belonging to a particular homologous series based on the data available from the other members of the same series. The study of organic compounds has been simplified.

1. Which of these statements is correct about the members of a homologous series?

(A) They have same empirical formula.

(B) They have same general formula.

(C) They have same molecular formula.

(D) They have same physical properties.

Ans. Option (B) is correct.

Explanation:

Homologous series is a series of 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. e.g., series of alkanes i.e., Methane, ethane, propane, butane and so on is a homologous series.

2. Two compounds CH3OH and C2H5OH provided. The difference in its formulae and molecular masses are are_I_ and_ II_.

(A) I-CH3 II- 16 units

(B) I-CH2, II- 14 units

(C) I-CH4, II- 18 units

(D) I- CH3, II-16 units

Ans. Option (B) is correct.

Explanation: CH3OH and C2H5OH are homologous because difference in its formulae and molecular masses are CH2 and 14 units.

3. What is the molecular formula of the 5th member of the homologous series of carbon compounds is represented by the general formula CnH2n+1 OH?

(A) C3H10

(B) C5H11OH

(C) C5H12OH

(D) C5H11CHO

Ans. Option (B) is correct

Explanation: The molecular formula of the fifth member of the homologous series of carbon compounds is represented by the general formula CnH2n+1OH is C5H11OH.

4. The general formula for alkene is:

(A) CnH2n

(B) CnH2n+2

(D) CnH2n-1

(C) CnH2n+2

Ans. Option (A) is correct.

Explanation: The General formula for alkenes are C2H2n, where n = number of carbon atoms. C2H4, C3H6, C4H8.

Subjective type questions

Very Short Answer Type Questions (1 Mark Each)

1. Define catenation.

Ans. The property of self-linking of atoms of an element through covalent bonds in order to form straight chain, branched chains or cyclic chains of different sizes is called catenation.

2. Name a cyclic unsaturated carbon compound.

Ans. Benzene.

3. Name the functional group present in propanone.

Ans. Ketone.

4. How are covalent bonds formed?

Ans. Covalent bonds are formed by the sharing of electrons between the atoms.

5. Write the molecular formula of first two members of homologous series having function group – Cl.

Ans. The molecular formula of first two consecutive members of this series is:

CH3CI (Chloromethane)

C2H5CI (Chloroethane)

6. Write the molecular formula of the 2nd and the 3rd member of the homologous series whose first member is methane.

Ans.

Ethane (C2H6)

Propane (C3H8)

7. Write the molecular formula of first two members of homologous series having functional group U -Br.

Ans. CH3Br, C2H5Br

8. Write the molecular formula of the 2nd and 3rd member of the homologous series whose first member is ethene.

Ans. C3H6 and C4H8

9. Write the molecular formula of the 2nd member of the homologous series where the first member is ethyne.

Ans. C3H4, C4H6

10. What is a homologous series of carbon compounds?

Ans. A homologous series is the family of organic com- pound having the same functional group, and the successive (adjacent) members of which differ by CH2 unit or 14 atomic mass unit.

11. Write the next homologue of each of the following:

(i) C2H4 (ii) C4H6

Ans. (i) C3H6 (ii) C5H8

12. Name the following compounds:

(i) CH3-CH2-OH, (ii) A picture containing text, device, meter, gaugeDescription automatically generated

Ans. (i) Ethanol, (ii) Ethanal.

13. Which element exhibits the property of catenation to maximum extent and why ?

Ans. Carbon, due to strong C-C bond.

14. Select saturated hydrocarbons from the followings: C3H6, C5H10, C4H10, C6H14, C2H4

Ans. C4H10, C6H14,

15. Write the name and structure of an alcohol with three carbon atoms in its molecule.

Ans. Propanol,

Diagram, schematicDescription automatically generated

16. Write the name and structure of an aldehyde with four carbon atoms in its molecule.

Ans. Butanal,

Diagram, schematicDescription automatically generated

OR

17. Name the process by which unsaturated fats gets changed to saturated fats.

Ans. Hydrogenation.

18. Write the name and formula of the 2nd member of homologous series having general formula Cn H2n.

Ans. Name: Propene Formula: C3H6

19. Write the number of covalent bonds in the molecule of ethane.

Short Answer Type Questions-l (2 Marks Each)

1. Give a test that can be used to confirm the presence of carbon in a compound. With a valency of 4, how is carbon able to attain noble gas configuration in its compounds?

Ans.

  • When carbon compound is burnt in the presence of oxygen, a gas is evolved.
  • Gas evolved turns lime water milky.
  • By sharing its four valence electrons with other elements, carbon attains stable noble gas configuration.

2. The number of carbon compounds is more than those formed by all other elements put together. Justify the statement by giving two reasons.

Ans.

  • Due to self linking ability of carbon/catenation.
  • Since carbon has a valency of four it can form bonds with four other atoms of carbon or atoms of some other monovalent element.
  • Due to small size of carbon, it forms very strong and (or) stable bonds with other elements.

3. Draw the structures for (i) ethanol, (ii) ethanoic acid.

Structure of ethanol:

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Structure of ethanoic acid:

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Short Answer Type Questions-Il (3 Marks Each)

1. Whatis a homologous series of carbon compounds? Give an example and list its three characteristics.

Ans. A series of compounds in which the same functional group substitutes for hydrogen in a carbon chain is called a homologous series.

Example: Alkane / Alkene / Alkyne / Alcohol or any other one correct example.

Characteristics:

(i) They have same general formula.

(ii) They have same functional group.

(iii) The difference in the molecular mass of two successive member is 14u.

(iv) The difference in the molecular formula of two successive member is of CH2 unit.

(v) They have similar chemical properties.

2. Which compounds are called (i) alkanes, (ii) alkenes and (iii) alkynes? C4H10 belongs to which of these? Draw two structural isomers of this compound.

Ans.

Alkane

Saturated hydrocarbon with C-C single bond

Alkene

Unsaturated Hydrocarbon with double bond in C=C

Alkyne

Unsaturated Hydrocarbon with triple bond in C=C

Alkane

2 structural isomers

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3. 

(a) Why most of the carbon compounds are poor conductor of electricity?

(b) Write the name and structure of a saturated compound in which the carbon atoms are arranged in a ring. Give the number of single bonds present in this compound.

Ans.

(a) Carbon compounds form covalent bonds/ do not dissociate into ions/do not have charged particles (ions)/do not have free electrons.

(b) Cyclohexane

Total no. of single bonds = 18

(OR any other cycloalkane with corresponding number of bonds)

4. What are covalent compounds? How are they different from ionic compounds? List any two properties of covalent compounds.

Ans.

( i ) The compounds that are formed due to sharing of electrons between two atoms/compounds having covalent bonds.

( ii ) Ionic compounds are formed due to transfer of electrons from one atom to another/compounds having ionic bonds/compounds having attraction between oppositely charged ions

  • They are poor conductors of electricity
  • They have low melting and boiling point.

5. Give reason why carbon can neither form C4+ cations nor C4- anions but forms covalent compounds. Also, state the reason to explain why covalent compounds are bad conductors of electricity and have low melting and boiling points?

Ans.

  • Carbon cannot form C4+ cation because removal of 4 electrons from a carbon atom would require a large amount of energy.
  • Carbon cannot form C4- anion because it would be difficult for the nucleus with 6 protons to hold on to 10 elec- trons.
  • Hence, carbon atoms share electrons forming covalent compounds.
  • Covalent compounds do not form ions/ charged particles and therefore do not conduct electricity.
  • Inter-molecular forces of attraction are weak; hence they have low melting and boiling points.

6. An aldehyde as well as a ketone can be represented by the same molecular formula, say C3H6O. Write their structures and name them. State the scientific relation between the two.

Ans.

  • Propanal (aldehyde);

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  • Propanone (Ketone); H. H. H- C-C-C -H H OH

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  • Isomers (same molecular formula but different structural formula/different functional group)

7. What is meant by isomers? Draw the structure of two isomers of butane, C4H10. Explain why we cannot have isomers of first three members of alkane series.

Ans. Isomers are the compounds which have the same molecular formula but different structural formula.

Isomers of Butane:

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We cannot have isomers of the first three members of the alkane series because of the following laws of isomers:

  1. The parent chain should have the greatest number of carbon atoms.
  2. The branching cannot be done from the first and the last carbon atom of the structure.

8. Draw the structures of the following compounds and identify the functional group present in them:

  1. Butanoic acid
  2. Bromopropane
  3. Butyne

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9. Write the molecular formula of the following compounds and draw their electron-dot structures:

(i). Ethane

(ii). Ethene

(iii). Ethyne

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Long Answer Type Questions (5 Marks Each)

1. What is methane ? Draw its electron dot structure. Name the type of bonds formed in this compound. Why are such compounds:

  1. poor conductors of electricity and
  2. have low melting and boiling points? What happens when this compound burns in oxygen?

Ans. CH4/Simplest hydrocarbon

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1. Covalent bonds

  • No ions or charged particles are formed
  • Due to weak covalent bonds

2. Carbon dioxide and water are produced/

CH4 + 202 → CO2 + 2H2O

Detailed Answer:

  • Methane is a colourless and highly flammable gas produced on decomposition of vegetation naturally in marshlands.
  • It is the simplest hydrocarbon (CH4).

Electron dot structure:

All the bonds present between four hydrogen atoms and one carbon atom at the centre are covalent bonds.

  1. Methane is a poor conductor of electricity as all the bonds presents are covalent bonds. Hence, no free electrons are available for conduction of electricity.
  2. As force of attraction between the molecules are not very strong in covalently bonded carbon compounds, therefore, methane being a covalent compound has very low melting and boiling point.

When methane burns in oxygen, carbon dioxide, water and large amount of heat and light is released.

CH4 + 2O2 → CO+2 2H20 + heat and light

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