CBSE Class 10 Science Chapter-4 Carbon and its Compounds Notes & NCERT Solution

Key Point: CBSE Class 10 Science Chapter 4 – “Carbon and its Compounds” Notes & NCERT Solutions

1. Introduction:

• Carbon is a versatile element forming the basis of a vast variety of compounds.
• The branch of chemistry that deals with the study of carbon compounds is known as organic chemistry.

1. Bonding in Carbon Compounds:

• Carbon readily forms covalent bonds with other elements, including itself.
• It can form single, double, and triple bonds, leading to the creation of diverse molecules.

1. Saturated and Unsaturated Carbon Compounds:

• Saturated compounds have single bonds, while unsaturated compounds have double or triple bonds between carbon atoms.

1. Functional Groups:

• Functional groups determine the properties and reactivity of organic compounds.
• Examples include hydroxyl (-OH), carboxyl (-COOH), amino (-NH2), and others.

1. Isomerism:

• Isomers are compounds with the same molecular formula but different structural arrangements.
• Structural isomerism and stereoisomerism are common types.

1. Nomenclature of Carbon Compounds:

• IUPAC rules are followed for naming organic compounds.
• Prefixes, infixes, and suffixes are used to denote various substituents and functional groups.

1. Chemical Properties of Carbon Compounds:

• Combustion, oxidation, addition, substitution, and esterification are common chemical reactions.
• Ethanol, acetic acid, and methane are examples.

1. Soaps and Detergents:

• Soaps and detergents are salts of fatty acids and play a crucial role in cleaning by emulsification and micelle formation.

1. Important Carbon Compounds:

• Methane, ethane, ethene, ethanol, acetic acid, glucose, and benzene are essential carbon compounds.

1. NCERT Solutions:

• Detailed solutions to NCERT textbook questions provided for better understanding and exam preparation.

These key points provide a concise overview of CBSE Class 10 Science Chapter 4, helping students grasp essential concepts related to carbon and its compounds.

NCERT Solutions for Class 10 Science Chapter 4 Intext Questions

Page Number: 61

Question 1:
What is the electron dot structure of carbon dioxide with the formula CO2?
Answer:
Refer to NCERT Solutions for Class 10 Science Chapter 4 Carbon and its Compounds Intext Questions p61 q1.

Question 2:
What is the electron dot structure of sulfur, consisting of eight sulfur atoms?
Answer:
Refer to NCERT Solutions for Class 10 Science Chapter 4 Carbon and its Compounds Intext Questions p61 q2.

Page Number: 68 – 69

Question 1:
How many structural isomers can you draw for pentane?
Answer:
Three structural isomers exist: n-pentane, iso-pentane, and neo-pentane.
Refer to NCERT Solutions for Class 10 Science Chapter 4 Carbon and its Compounds Intext Questions p68 q1.

Question 2:
Name two properties of carbon responsible for the abundance of carbon compounds.
Answer:
(i) Tetravalency
(ii) Catenation.
Refer to NCERT Solutions for Class 10 Science Chapter 4 Carbon and its Compounds Intext Questions p68 q2.

Question 3:
Provide the formula and electron dot structure of cyclopentane.
Answer:
The molecular formula is C5H10. The electron dot structure is on the next page.
Refer to NCERT Solutions for Class 10 Science Chapter 4 Carbon and its Compounds Intext Questions p68 q3.

Question 4:
Draw structures for the compounds:
(i) Ethanoic acid
(ii) Bromopentane
(iii) Butanone
(iv) Hexanal
Answer:
Refer to NCERT Solutions for Class 10 Science Chapter 4 Carbon and its Compounds Intext Questions p68 q4.
(i) Ethanoic acid (CH3COOH)
(ii) Bromopentane (C5H11Br)
(iii) Butanone (CH3 — CH2 — COCH3)
(iv) Hexanal (C5H11CHO)
Structural isomers for bromopentane: Three structural isomers exist, depending on the position of Br at carbon 1, 2, 3. Positions 4 and 5 are the same as 1, 2.
Refer to NCERT Solutions for Class 10 Science Chapter 4 Carbon and its Compounds Intext Questions p68 q4d.

Question 5:
Name the following compounds:
(i) Bromoethane
(ii) Methanal
(iii) 1 – Hexyne
Answer:
Refer to NCERT Solutions for Class 10 Science Chapter 4 Carbon and its Compounds Intext Questions p68 q5.
(i) Bromoethane
(ii) Methanal
(iii) 1 – Hexyne

Page Number: 71

Question 1:
Explain why the conversion of ethanol to ethanoic acid is an oxidation reaction.
Answer:
The conversion of ethanol to ethanoic acid is oxidation because the addition of oxygen to a substance is called oxidation. Oxygen is added to ethanol by oxidizing agents like alkaline potassium permanganate or acidified potassium dichromate, converting it into an acid.
Refer to NCERT Solutions for Class 10 Science Chapter 4 Carbon and its Compounds Intext Questions p71 q1.

Question 2:
For welding, why is a mixture of oxygen and ethyne burnt, and not a mixture of ethyne and air?
Answer:
A mixture of ethyne and air is not used for welding because burning ethyne in air produces a sooty flame due to incomplete combustion, which is insufficient to melt metals for welding.

Page Number: 74

Question 1:
How would you experimentally distinguish between alcohol and carboxylic acid?
Answer:
Differences:
(i) Litmus test: Alcohol – No change in color, Carboxylic acid – Blue litmus solution turns red.
(ii) Sodium hydrogen carbonate test: Alcohol – No reaction, Carboxylic acid – Brisk effervescence due to the evolution of CO2.
(iii) Alkaline potassium permanganate: Alcohol – On heating, pink color disappears, Carboxylic acid – No change.
Refer to NCERT Solutions for Class 10 Science Chapter 4 Carbon and its Compounds Intext Questions p74 q1.

Question 2:
Define oxidizing agents.
Answer:
Oxidizing agents are substances that provide oxygen to other substances or remove hydrogen from a substance. Acidic K2Cr2O7 is an oxidizing agent that converts ethanol into ethanoic acid.
Refer to NCERT Solutions for Class 10 Science Chapter 4 Carbon and its Compounds Intext Questions p74 q2.

Page Number: 76

Question 1:
Can you determine if water is hard using a detergent?
Answer:
No, because detergents can lather well even in hard water. They do not form insoluble calcium or magnesium salts (scum) when reacting with the calcium ions and magnesium ions present in hard water.

Question 2:
Why is agitation necessary in washing clothes using soap?
Answer:
Agitation is necessary to remove soap micelles containing oily or greasy particles from the surface of dirty cloth. When the cloth wetted in soap solution is agitated or beaten, the micelles with dirt get removed, and the cloth gets cleaned.
Refer to NCERT Solutions for Class 10 Science Chapter 4 Carbon and its Compounds Intext Questions p76 q2.

NCERT Solutions for Class 10 Science Chapter 4 Textbook Chapter End Questions

Question 1:
Ethane, with the molecular formula C2H6, has
(a) 6 covalent bonds
(b) 7 covalent bonds
(c) 8 covalent bonds
(d) 9 covalent bonds.
Answer:
(b) 7 covalent bonds.

Question 2:
Butanone is a four-carbon compound with the functional group
(a) carboxylic acid
(b) aldehyde
(c) ketone
(d) alcohol.
Answer:
(c) Ketone.

Question 3:
While cooking, if the bottom of the vessel is getting blackened on the outside, it means that
(a) the food is not cooked completely.
(b) the fuel is not burning completely.
(c) the fuel is wet.
(d) the fuel is burning completely.
Answer:
(b) The fuel is not burning completely.

Question 4:
Explain the nature of the covalent bond using the bond formation in CH3Cl.
Answer:
Covalent bonds are formed by sharing electrons so that the combining atoms complete their outermost shell. In CH3Cl, carbon shares its four electrons with three hydrogen atoms and one chlorine atom, forming single covalent bonds.

Question 5:
Draw the electron dot structures for
(a) ethanoic acid
(b) propanone
(c) H2S
(d) F2.
Answer:
Refer to NCERT Solutions for Class 10 Science Chapter 4 Textbook Chapter End Questions Q5.

Question 6:
What is a homologous series? Explain with an example.
Answer:
A homologous series is a group of organic compounds with similar structures and chemical properties, where successive compounds differ by -CH2 group. For example, the homologous series of alkanes has the general formula CnH2n+2, with the first five members being methane, ethane, propane, butane, and pentane.

Question 7:
How can ethanol and ethanoic acid be differentiated based on their physical and chemical properties?
Answer:
Refer to NCERT Solutions for Class 10 Science Chapter 4 Textbook Chapter End Questions Q7.

Question 8:
Why does micelle formation take place when soap is added to water? Will a micelle be formed in other solvents such as ethanol also?
Answer:
Micelle formation occurs when soap is added to water because soap molecules have hydrophobic (water-repelling) hydrocarbon chains and hydrophilic (water-attracting) ionic ends. Micelle formation is not possible in solvents like ethanol where sodium salt of fatty acids does not dissolve.

Question 9:
Why are carbon and its compounds used as fuels for most applications?
Answer:
Carbon and its compounds provide a large amount of heat per unit weight, making them suitable fuels for various applications.

Question 10:
Explain the formation of scum when hard water is treated with soap.
Answer:
Hard water contains calcium and magnesium salts. When soap reacts with these salts, it forms insoluble precipitates called scum, reducing the cleansing properties of soap in hard water.

Question 11:
What change will you observe if you test soap with litmus paper (red and blue)?
Answer:
Red litmus turns blue when tested with soap because soap is alkaline in nature. Blue litmus remains blue in soap solution.

Question 12:
What is hydrogenation? What is its industrial application?
Answer:
Hydrogenation is the addition of hydrogen to an unsaturated hydrocarbon to obtain a saturated hydrocarbon. It is used industrially to prepare vegetable ghee (or vanaspati ghee) from vegetable oils.

Question 13:
Which of the following hydrocarbons undergo addition reactions: C2H6, C3H8, C3H6, C2H2, and CH4?
Answer:
Addition reactions occur only in unsaturated hydrocarbons. So, C3H6 and C2H2 undergo addition reactions.

Question 14:
Give a test that can be used to differentiate chemically between butter and cooking oil.
Answer:
Addition of bromine water can be used to differentiate chemically between butter and cooking oil. Cooking oil (unsaturated) decolorizes bromine water, while butter (saturated) does not.

Question 15:
Explain the mechanism of the cleaning action of soaps.
Answer:
When soap is added to water, hydrocarbon ends of soap molecules in micelles attach to oil or grease particles on a dirty cloth. The cloth is cleaned as these micelles disperse the particles in water when agitated. The ionic ends of soap molecules remain attached to water. Rinsing the cloth in clean water removes the dispersed particles, leaving the cloth clean.

CBSE Class 10 Multiple Choice Questions Chapter-4 Carbon and its Compounds

CBSE Class 10 Science Chapter-4 Carbon and its Compounds:

1. Which of the following statements are correct for carbon compounds?
   (a) Most carbon compounds are good conductors of electricity.
   (b) Most carbon compounds are poor conductors of electricity.
   (c) Force of attraction between molecules of carbon compounds is not very strong.
   (d) Force of attraction between molecules of carbon compounds is very strong.
   Answer: (b) (ii) and (iii)
2. C3H8 belongs to the homologous series of
   (a) Alkynes
   (b) Alkenes
   (c) Alkanes
   (d) Cyclo alkanes
   Answer: (c) Alkanes
3. Which of the following is the formula of Butanoic acid?
   Answer: C4H8O2
4. The number of isomers of pentane is
   (a) 2
   (b) 3
   (c) 4
   (d) 5
   Answer: (c) 4
5. Which of the following will undergo addition reactions?
   (a) CH4
   (b) C3H8
   (C) C2H6
   (d) C2H4
   Answer: (d) C2H4
6. When ethanoic acid is treated with NaHCO3 the gas evolved is
   (a) H2
   (b) CO2
   (c) CH4
   (d) CO
   Answer: (b) CO2
7. Ethanol on complete oxidation gives
   (a) acetic acid/ethanoic acid
   (b) CO2 and water
   (c) ethanal
   (d) acetone/ethanone
   Answer: (b) CO2 and water
8. Which of the following will give a pleasant smell of ester when heated with ethanol and a small quantity of sulphuric acid?
   (a) CH3COOH
   (b) CH3CH2OH
   (c) CH3OH
   (d) CH3CHO
   Answer: (d) CH3CHO
9. Name the functional group present in CH3COCH3.
   (a) Alcohol
   (b) Carboxylic acid
   (c) Ketone
   (d) Aldehyde
   Answer: (c) Ketone
10. Why does carbon form compounds mainly by covalent bonding?
    (a) There are four electrons in the outermost shell of carbon.
    (b) It requires large amount of energy to form C4+ or C4-.
    (c) It shares its valence electrons to complete its octet.
    (d) All the above.
    Answer: (d) All the above.

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