# NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

Written by Team Trustudies
Updated at 2021-05-07

Carbon and its compounds is the fourth(4th) chapter of CBSE class 10 science. We have produced complete ncert solutions for class 10 science chapter 4 carbon and its compounds with detailed solutions to each and every question of chapter 4 class 10 science. Chapter 4 class 10 science (Carbon and its compounds ) is a very important chapter and deals with different types of topics and is a gateway to organic chemistry.

Ncert solutions for class 10 science chapter 4 carbon and its compounds will be very helpful for all the students of CBSE class 10 who want to make a strong base in organic chemistry and score good marks in exams. These solutions are already used by many students of class 10 at Trustudies. Ncert solutions for class 10 science chapter 4 carbon and its compounds is best in class in terms of quality as they are made by our expert team and verified by many top teachers of class 10.

class 10 science chapter 4 carbon and its compounds contain topics like bonding in carbon , versatile nature of carbon, the nomenclature of carbon compounds, chemical properties of carbon compounds like combination and oxidation , addition reaction, substitution reaction, acids like ethanoic acid

## NCERT solutions for class 10 Science Chapter 4 Carbon And Its Compounds Exercise

Q1 )

Ethane, with the molecular formula${C}_{2}{H}_{6}$ has

• (a) 6 covalent bonds
• (b) 7 covalent bonds
• (c) 8 covalent bonds
• (d) 9 covalent bonds

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

Option (b) 10, The carbon atoms have 4 atoms in outer most cell and hydrogen atom has one in outer most cell....
the 6 hydrogen atoms will share their electron with carbon atom to form 6 carbon - hydrogen covalent bonds and the two carbon atom will share 1 electron from each to form 1 carbon - carbon covalent bond... thus the ethane have 7 covalent bonds in total.

Q2 )

Butanone is a four-carbon compound with the functional group

• (a) Carboxylic acid
• (b) Aldehyde
• (c) Ketone
• (d) Alchohol

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

Option (C)

##### Butanone

Q3 )

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.

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

Option (b) the fuel is not burning completely.

Q4 )

Explain the nature of the covalent bond using the bond formation in $C{H}_{3}Cl.$

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

Carbon can neither lose four of its electrons nor gain four electrons as both the processes require extra amount of energy and would make the system unstable. Therefore, it completes its octet by sharing its four electrons with other carbon atoms or with atoms of other elements. The bonds that are formed by sharing electrons are known as covalent bonds. In covalent bonding, both the atoms share the valence electrons, i.e., the shared electrons belong to the valence shells of both the atoms.

Here, carbon requires 4 electrons to complete its octet, while each hydrogen atom requires one electron to complete its duplet. Also, chlorine requires an electron to complete the octet. Therefore, all of these share the electrons and as a result, carbon forms 3 bonds with hydrogen and one with chlorine.

Q5 ) Draw the electron dot structures for

• (a)Ethanoic acid
• (b) H2S
• (c)Propanone
• (d)F2

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

Ethanoic acid

H2S

Propanone

F2 v

Q6 ) What is a homologous series? Explain with an example.

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

A homologous series is a series of carbon compounds that have different numbers of carbon atoms but contain the same functional group. For example, methane, ethane, propane, butane, etc. are all part of the alkane homologous series.

The general formula of this series is CnH2n+2

• Methane - CH4
• Ethane - CH3CH3
• Propane - CH3CH2CH3
• Butabe - CH3CH2CH2CH3

It can be noticed that there is a difference of ?CH2 unit between each successive compound.

Q7 ) How can ethanol and ethanoic acid be differentiated on the basis of their physical and chemical properties?

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

Difference between Ethanol and Ethanoic acid

1. Ethanol has the molecular formula C2H5OH, while ethanoic acid has the molecular formula C2H4O2.
2. Ethanol has an ethyl group while ethanoic acid has a methyl group.
3. Ethanoic acid is a carboxylic acid; this is not the case for ethanol.
4. Ethanol has a hydroxyl group while ethanoic acid has a carboxyl group.
5. Ethanol in a pure state is basic, while ethanoic acid is acidic.
6. Ethanoic acid has a boiling point of 118 to 119oC, while ethanol has a boiling point of 78.5
7. Ethanoic acid has a vinegar smell while ethanol has a perfume type of smell.
8. Ethanoic acid can be formed using Acetobacter bacteria during fermentation; this is not the case with ethanol.
9. Ethanol usually is formed using yeasts such as Saccharomyces cerevisiae or Schizosaccharomyces during fermentation; this is not the case with ethanoic acid.
10. Ethanol is used to make alcoholic beverages while ethanoic acid is used to make vinegar.
11. Ethanol is also referred to as ethyl alcohol while ethanoic acid is also referred to as acetic acid.
12. Ethanol does not react with metal carbonates while, ethanoic acid reacts with metal carbonates to form salt, water and carbon dioxide. For example, $2C{H}_{3}COOH+N{a}_{2}C{O}_{3}$ $?$ $2C{H}_{3}COONa+C{O}_{2}+{H}_{2}O$
13. Ethanol does not react with NaOH while ethanoic acid reacts with NaOH to form sodium ethanoate and water.
Ex :
Ethanol is oxidized to give ethanoic acid in presence of acidified KMnO4 while, no reaction takes place with ethanoic acid in presence of acidified KMnO4.

Q8 ) Why does micelle formation take place when soap is added to water? Will a micelle be formed in other solvents such as ethanol also?

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

Soap molecule has two ends. One end is hydrophilic and another end is hydrophobic. When soap is dissolved in water and clothes are put in the soapy solution, soap molecules converge in a typical fashion to make a structure; called micelle. The hydrophobic ends of different molecules surround a particle of grease and make the micelle; which is a spherical structure. In this, the hydrophilic end is outside the sphere and hydrophobic end is towards the centre of the sphere. This is why micelle formation takes place when soap is added to water. Since ethanol is not as polar as soap, so micelles will not be formed in other solvents such as ethanol.

Q9 ) Why are carbon and its compounds used as fuels for most applications?

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

Carbon and its compounds give large amount of heat on combustion due to high percentage of carbon and hydrogen. Carbon compounds used as fuel have optimum ignition temperature with high calorific values and are easy to handle. Their combustion can e controlled. Therefore, carbon and its compounds are used as fuels.

Q10 ) Explain the formation of scum when hard water is treated with soap.

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

Hard water often contains salts of calcium and magnesium. Soap molecules react with the salts of calcium and magnesium and form a precipitate. This precipitate begins floating as an off-white layer over water. This layer is called scum. Soaps lose their cleansing property in hard water because of formation of scum.

Q11 ) What change will you observe if you test soap with litmus paper (red and blue)?

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

Since soap is basic in nature, it will turn red litmus blue. However, the colour of blue litmus will remain blue.

Q12 ) What is hydrogenation? What is its industrial application?

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

Hydrogenation is the chemical reaction between hydrogen and other compounds in the presence of catalyst. Hydrogenation is used mainly to reduce saturated hydrocarbons. Hydrogenation is an addition reaction.For Example: When ethene is heated with the catalyst nickel it is reduced to ethane.

Industrial application: Hydrogenation is used in many industrial applications. For example; in Petrochemical Industry, hydrogenation is used to convert alkenes into alkanes (paraffins) and cycloalkanes. ? It is also used to prepare vegetable ghee from vegetable oils.

Q13 ) Which of the following hydrocarbons undergo addition reactions: ${C}_{2},{H}_{6},{C}_{3}{H}_{8},{C}_{3}{H}_{6},{C}_{2}{H}_{2}andC{H}_{4}.$

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

Unsaturated hydrocarbons undergo addition reactions. Being unsaturated hydrocarbons, ${C}_{3}{H}_{6}$. and $,{C}_{2}{H}_{2}$ undergo addition reactions.

## NCERT solutions for class 10 Science Chapter 4 Carbon And Its Compounds Intext Exercise

Q1 ) What would be the electron dot structure of carbon dioxide which has the formula $C{O}_{2}$?

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

Electron dot structure of carbon dioxide:

Q2 ) What would be the electron dot structure of a molecule of sulphur which is made up of eight atoms of sulphur? (Hint–The eight atoms of sulphur are joined together in the form of a ring.)

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

Q3 ) How many structural isomers can you draw for pentane?

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

Pentane has three structural isomers named as n-pentane, Iso-pentane and neo-pentane. Structures of these isomers are:

Q4 ) What are the two properties of carbon which lead to the huge number of carbon compounds we see around us?

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

The 2 properties that makes carbon to form a very large number of compounds are:

1. Catenation: Catenation is the property of forming C-C chains to a large number of carbons. Besides Carbon, only Silicon has this property, but do not form such large compounds as that of carbon.
2. Tetravalency: Carbon has the Covalent nature with a valency of 4 which makes it to form numerous chain, ringed, Aromatic compounds by nature. Hence the number of carbon compounds exist in large numbers as compared to the compounds formed by all other elements.

Q5 ) What will be the formula and electron dot structure of cyclopentane?

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

Formula of cyclopentane is ${C}_{5}{H}_{10}$.

Q6 ) Draw the structures for the following compounds.

1. Ethanoic acid
2. Bromopentane*
3. Butanone
4. Hexanal.

5. *Are structural isomers possible for bromopentane?

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

The structures for the compounds are:

Yes,structural isomers of bromopentane are possible and are as follows:

Q7 ) How would you name the following compounds?

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

(i) Bromoethane.
Explanation:presence of bromo group with two carbon atoms.
(ii) Methanal.
Explanation:presence of an aldehyde group in this compound with one carbon atom.
(iii) Hexyne.
Explanation: presence of a triple bond with six carbon atoms.

Q8 ) Why is the conversion of ethanol to ethanoic acid an oxidation reaction?

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

The addition of oxygen to a substance is called oxidation and here as per the reaction, in the conversion of ethanol to ethanoic acid , one oxygen is added to ethanol, hence it is an oxidation reaction.The reaction is as follows:

Q9 ) A mixture of oxygen and ethyne is burnt for welding. Can you tell why a mixture of ethyne and air is not used?

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

Mixture of ethyne and air is not used for welding because when ethyne is burnt in air ,incomplete burning takes place and produces sooty flame due to limited supply of oxygen present in the air, whereas when mixture of oxygen and ethyne is burnt, it gives high temperature because of complete combustion and gives clean flame. Hence, this is the reason, oxygen is used instead of air to burn ethyne and is used for welding.

Q10 ) How would you distinguish experimentally between an alcohol and a carboxylic acid?

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

We can distinguish between an alcohol and a carboxylic acid on the basis of their reaction with carbonates and hydrogen carbonates. Acid reacts with carbonate and hydrogen carbonate to evolve $C{O}_{2}$ gas that turns lime water milky. On the other hand, alcohols do not react with carbonates and hydrogen carbonates so there won’t be any evolution of $C{O}_{2}$ gas .Thus, the reaction with carbonate or hydrogen carbonate can be used to distinguish between carboxylic acid and alcohol.

Q11 ) What are oxidising agents?

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

A substance that has the ability to oxidize other substances or in other words, a substance that has the ability to give oxygen or replace hydrogen on reaction with other compounds are called oxidising agents .Example : oxygen, halogens etc.

Q12 ) Would you be able to check if water is hard by using a detergent?

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

It is not possible to check if water is hard by using a detergent because detergent gives lather with hard and soft water both.Whereas, a soap can be used to check if water is hard because soap gives lather with soft water only.

Q13 ) People use a variety of methods to wash clothes. Usually after adding the soap, they ‘beat’ the clothes on a stone, or beat it with a paddle, scrub with a brush or the mixture is agitated in a washing machine. Why is agitation necessary to get clean clothes?

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

As we know soaps and detergents form a micelle around the oily dirt particle but it still forms a colloid.To remove dirt in the form of micelles from clothes agitation helps to loosen the dirt particle and is necessary to get clean clothes.

Q.14 Give a test that can be used to differentiate between saturated and unsaturated hydrocarbons.

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds

Butter contains saturated fats. Therefore, it cannot be hydrogenated. On the other hand, oil has unsaturated fats. That is why it can be hydrogenated to saturated fats (solids).

Q.15 Explain the mechanism of the cleaning action of soaps.

NCERT Solutions for Class 10 Science Chapter 4 Carbon And Its Compounds