Class 10 Science Chapter 4 Carbon and Its Compounds
Are you looking for the best notes and question answers for Class 10 Science Chapter 4 Carbon and Its Compounds? You are in the right place. This chapter is one of the most important topics in Class 10 Science and plays a key role in building a strong foundation in Organic Chemistry. Here, you will find easy-to-understand notes, textbook question answers, important concepts, and exam-oriented study materials designed to help you prepare with confidence.
In this chapter, you will learn about the unique properties of carbon, covalent bonding, the versatile nature of carbon, hydrocarbons, saturated and unsaturated compounds, homologous series, functional groups, and the naming of carbon compounds. You will also study important chemical reactions, the properties and uses of ethanol and ethanoic acid, and understand how soaps and detergents work in everyday life.
Whether you are preparing for class tests, annual examinations, or the HSLC Board Examination, this chapter will help you strengthen your concepts, improve your problem-solving skills, and score higher marks in Science.
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- 📘 Easy & Simple Chapter Notes
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Start learning Class 10 Science Chapter 4 Carbon and Its Compounds today and make your Science preparation easier, smarter, and more effective.
Carbon and Its Compounds
Selected Questions &Answers
Q: What is a catalyst?
Ans: A catalyst is a substance that increases the rate of a reaction without undergoing any change in its own properties.
Q: What is an addition reaction or hydrogenation?
Ans: Reactions in which hydrogen is added in the presence of a catalyst are called addition reactions.
Q: What is catenation?
Ans: Carbon can form bonds with itself to create a large number of compounds. This property is called ‘catenation.’
Q: What is a saturated compound?
Ans: Compounds in which carbon atoms are connected by single bonds are called saturated compounds.
Q: Define unsaturated compounds.
Ans: Compounds in which carbon atoms are connected by double or triple bonds are called unsaturated compounds.
Q: Define alkane, alkene and alkyne.
Ans: Alkane: Saturated hydrocarbons are called alkanes.
Alkene: Unsaturated compounds having one or more double bonds are called alkenes.
Alkyne: Compounds having triple bonds are called alkynes.
Q: Write the formula of cyclohexane.
Ans: C₆H₁₂
Q: Give an example of a homologous series.
Ans: CH₃OH, C₂H₅OH, C₃H₇OH, C₄H₉OH
Q: What is an oxidising agent? Give an example.
Ans: Substances that can supply oxygen in a reaction are called oxidising agents. Example: Potassium dichromate.
Q: Write one use of addition reaction.
Ans: Addition reactions are used to produce vanaspati ghee by adding hydrogen to vegetable oils.
Q: Why is the conversion of ethanol to ethanoic acid an oxidation reaction?
Ans: During the conversion of ethanol to ethanoic acid, oxygen is added.
Therefore, it is called an oxidation reaction.
Q: Why is the conversion of ethanol to ethanoic acid an oxidation reaction? HSLC ’18
Ans: During the conversion of ethanol to ethanoic acid, oxygen is added to ethanol. Therefore, it is called an oxidation reaction.
Q: During welding, oxygen and ethyne are used for combustion. Why is air not used with ethyne?
Ans: Combustion of ethyne with oxygen produces a large amount of heat, which is suitable for welding. But in air, nitrogen is present, which does not support efficient combustion and reduces the heat produced.
Q: What is an oxidising substance?
Ans: A substance used to oxidise another substance is called an oxidising substance.
Q: Can hardness of water be detected using soap?
Ans: The hardness of water can be detected using soap. Hard water does not produce lather easily with soap.
Q: How can you distinguish between alcohol and carboxylic acid by an experiment? HSLC ‘20
Ans: Take saturated sodium bicarbonate solution in two test tubes. Add alcohol to one and carboxylic acid to the other. The solution in which carbon dioxide gas is produced is the carboxylic acid, while the other is alcohol.
Q: In an ethane (C₂H₆) molecule—
(a) 6 covalent bonds are present
(b) 7 covalent bonds are present
(c) 4 covalent bonds are present
(d) 9 covalent bonds are present
Ans: (b) 7 covalent bonds are present
Q: The functional group present in butanone (a four-carbon compound)is—
(a) Carboxylic acid
(b) Aldehyde
(c) Ketone
(d) Alcohol
Ans: (c) Ketone
Q: The bottom of cooking vessels becomes black because—
(a) Food is not cooked properly
(b) Fuel does not burn completely
(c) Fuel is wet
(d) Fuel burns completely
Ans: (b) Fuel does not burn completely
Q: What is a homologous series? Explain with an example. HSLC ’16
Ans: A homologous series is a group of organic compounds having similar chemical properties and represented by the same general formula.
Example: Alkanes such as methane (CH₄), ethane (C₂H₆), propane (C₃H₈), butane (C₄H₁₀), pentane (C₅H₁₂), hexane (C₆H₁₄).
Q: Write the differences between ethanol and ethanoic acid based on physical and chemical properties.
Ans: The differences between ethanol and ethanoic acid are:
Ethanol has no effect on litmus solution.
Ethanoic acid turns blue litmus red.
Ethanol has a pleasant smell.
Ethanoic acid has a vinegar-like smell.
Ethanol does not produce any gas with sodium bicarbonate.
Ethanoic acid produces CO₂gas with sodium bicarbonate.
Q: Why are carbon and its compounds used as fuels in most cases?
Ans: Carbon and its compounds produce a large amount of heat on combustion, so they are used as fuels.
Q: What is hydrogenation? Write its industrial application.
Ans: Hydrogenation is the process in which unsaturated hydrocarbons react with hydrogen in the presence of a catalyst like nickel or palladium to form saturated hydrocarbons.
Industrial application: It is used in the preparation of vanaspati ghee from vegetable oils using a nickel catalyst.
Q: What will you observe when testing soap with blue and red litmus paper?
Ans: Soap is basic in nature. Therefore, it turns red litmus blue.
Q: Which of the following hydrocarbons show addition reaction?
C₂H₆, C₃H₈, C₃H₆, C₂H₂ and CH₄
Ans: C₃H₆ and C₂H₂
Q: Describe an experiment to distinguish between butter and cooking oil.
Ans: Bromine water can be used to distinguish between cooking oil and butter. Cooking oil decolourises bromine water, while butter does not react with it.
Q: Explain the cleaning action of soap. HSLC ’20
Ans: Most dirt is oily in nature. Soap molecules are sodium or potassium salts of long-chain carboxylic acids. The ionic end is soluble in water, while the carbon chain is insoluble in water but soluble in oil. Soap forms micelles in water, trapping dirt and helping in its removal.
Q: Identify the alkene from the following—
(a) C₄H₈
(b) C₄H₁₀
(c) C₄H₆
(d) C₂H₆
Ans: (a) C₄H₈
Q: The COOH group belongs to which class of compounds?
Ans: Carboxylic acids
Q: What is catenation? HSLC ‘20
Ans: The property by which carbon atoms form long chains by bonding with each other through C–C bonds is called catenation.
Q: Why are alkenes and alkynes more chemically reactive?
Ans: Alkenes and alkynes are more chemically reactive because they contain multiple bonds (double or triple bonds) between carbon atoms.
Q: What are functional groups? Give two examples.
Ans: A functional group is an atom or a group of atoms that replaces a hydrogen atom in a hydrocarbon chain and determines the chemical properties of the compound. Examples: Ketone, aldehyde.
Q: Write two properties of covalent compounds.
Ans: (a) Covalent compounds have low melting and boiling points.
(b) Covalent compounds are poor conductors of electricity.
Q: Write two physical properties and two uses of ethanol.
Ans: Two physical properties of ethanol are—
(a) It is a colourless liquid at room temperature.
(b) It is volatile and burns with a blue flame.
Two uses of ethanol are—
(a) It is used as the main component in alcoholic beverages.
(b) It is used as a solvent in perfumes, medicines, etc.
Q: Write the names of two alkanes.
Ans: Two alkanes are methane and ethane.
Q: During welding, a mixture of oxygen and ethyne is used for combustion. Why is a mixture of ethyne and air not used? Explain. HSLC ’19
Ans: When ethyne burns in air, it produces a yellow sooty flame with less heat, which is not sufficient for welding. But when it burns in pure oxygen, it produces a hot blue flame with a large amount of heat. Therefore, a mixture of oxygen and ethyne is used in welding.
Q: What are the ions present in NaCl compound? HSLC ’19
Ans: The ions present in NaCl are Na⁺ and Cl⁺.
Q: Explain the process of cleaning action of soap. HSLC ’18
Ans: Soap ions form a special structure around oily dirt particles. When washed with water, these structures help to remove the dirt from clothes.
Q: Which two properties of carbon are responsible for the large number of carbon compounds around us? HSLC ’16
Ans: The two properties are—
(a) Catenation property of carbon
(b) Tetravalency of carbon
Q: Explain substitution reaction with an example. HSLC ’18
Ans: A substitution reaction is a reaction in which one atom or group in a compound is replaced by another atom or group.
Example: CH₄ + Cl₂ → CH₃Cl + HCl (in presence of sunlight)
Q: Which of the following hydrocarbons show addition reaction? HSLC’19
C₂H₂, C₃H₈, C₃H₆, C₂H₂, CH₄
Ans: The hydrocarbons that show addition reactions are: C₂H₂ and C₃H₆.
Multiple Choice Questions (MCQ)
Q: In a limited supply of air, saturated hydrocarbons generally produce—
(a) Green flame
(b) Yellow flame with black smoke
(c) Non-sooty flame
(d) Clean blue flame
Ans: (b) Yellow flame with black smoke
Q: All compounds of a homologous series show the same type of—
(a) Chemical composition
(b) Chemical reaction
(c) Chemical properties
(d) None of the above
Ans: (c) Chemical properties
Q: The atomic number of chlorine is 17. Its valency is—
(a) 2
(b) 1
(c) 7
(d) 0
Ans: (b) 1
Q: In one molecule of propane—
(a) 10 covalent bonds are present
(b) 9 covalent bonds are present
(c) 4 covalent bonds are present
(d) 11 covalent bonds are present
Ans: (a) 10 covalent bonds are present
Q: The functional group present in propanone is—
(a) Aldehyde
(b) Carboxylic acid
(c) Ketone
(d) Alcohol
Ans: (c) Ketone
Q: The type of reaction in which alkanes generally take part is—
(a) Addition reaction
(b) Oxidation-reduction reaction
(c) Substitution reaction
(d) Polymerisation reaction
Ans: (c) Substitution reaction
Q: Unsaturated hydrocarbons generally produce—
(a) Green flame
(b) Yellow flame with black smoke
(c) Non-sooty flame
(d) Clean blue flame
Ans: (b) Yellow flame with black smoke
Q: Which of the following is an oxidising agent?
(a) Hydrogen peroxide
(b) Iron chloride
(c) Sulphuric acid
(d) Alkaline potassium permanganate
Ans: (d) Alkaline potassium permanganate
Q: Which of the following shows a closed chain?
(a) Cyclopentane
(b) Cyclomethane
(c) Butane
(d) Pentane
Ans: (a) Cyclopentane
Q: What percentage of acetic acid is present in vinegar?
(a) 9–12%
(b) 5–8%
(c) 1–2%
(d) 3–5%
Ans: (b) 5–8%
