NCERT Solutions Class 10 for Science Chapter 4 Carbon and it’s Compounds

NCERT Solutions Class 10 for Science Chapter 4 Carbon and it’s Compounds : In this post, we will share with you all the detailed NCERT Solutions of Class 10 Science Chapter 4 Carbon and it’s Compounds . This will contain both in-text and back-exercise questions for Science and Social Science, and all exercise questions for Mathematics. For all school and board level examinations, doing all the NCERT Questions is a must.

Why are NCERT Questions Important?

NCERT Questions and Answers not only help you get hold of concepts firmly and enhance your understanding, but also form the base of all types of questions asked in exams. Questions asked in exam are more or less the same type as mentioned in NCERT. Moreover, sometimes the questions in NCERT are directly asked in exams, as it is, without any changes.

Hence, it’s very important to understand NCERT Questions and Answers.

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Class 10 Science Chapter 4 – Carbon and Its Compounds


In-Text Questions SET 1 (Page 61)

Question 1:
What would be the electron dot structure of carbon dioxide which has the formula CO2 ?

Answer 1:

Question 2:
What would be electron dot structure of sulphur which is made up of eight atoms of sulphur?

Answer 2:

In-Text Questions SET 2 (Page 68-69)

Question 1:
How many structural isomers can you draw for pentane?

Answer 1:
Structural isomer of pentane are-

2, 2-dimethylpropane

Question 2:
What are the two properties of carbon which lead to the huge number of carbon compounds we see around us?

Answer 2:
Two properties of carbon which lead to the huge number of carbon compounds we see around us are

  • Carbon has six valence electrons which are actually a high number of valency.
  • Covalent bonding happens easily with carbon atoms and numerous others such as oxygen, chlorine, nitrogen, Sulphur, hydrogen, etc.

Question 3:
What will be the formula and electron dot structure of cyclopentane?

Answer 3:

Question 4:
Draw the structures for the following compounds.

(i) Ethanoic acid
(ii) Bromopentane*
(iii) Butanone
(iv) Hexanal

Answer 4:




Question 5:
How would you name the following compounds ?

Answer 5:

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In-Text Questions SET 3 (Page 71)

Question 1:
Why is the conversion of ethanol to ethanoic acid an oxidation reaction ?

Answer 1:
Conversion of ethanol into ethanoic acid is an oxidation reaction because addition of oxygen to a substance is called oxidation. Here, oxygen is added to ethanol by oxidising agent like alkaline potassium permanganate or acidified potassium dichromate and it is converted into acid.

Question 2:
A mixture of oxygen and ethyne is burnt for welding. Can you tell why a mixture of ethyne and air is not used ?

Answer 2:
A mixture of ethyne and air is not used for welding because burning of ethyne in air produces a sooty flame due to incomplete combustion, which is not enough to melt metals for welding.

In-Text Questions SET 4 (Page 74)

Question 1:
How would you distinguish experimentally between an alcohol and a carboxylic acid?

Answer 1:
On reaction with Sodium Carbonate, Carboxylic acids produces carbon dioxide gas which turns lime water milky whereas alcohols do not give this reaction. This experiment can be used to distinguish an alcohol and carboxylic acid.

Reaction of Carboxylic acid with sodium carbonate:

2CH3COOH + Na2CO3 → 2CH3COONa + H2O + CO2


Question 2:
What are oxidising agents ?

Answer 2:
Oxidising agents are those compounds which either removes Hydrogen or adds oxygen to a compound. Ex: halogens, potassium nitrate, and nitric acid.

In-Text Questions SET 5 (Page 76)

Question 1:
Would you be able to check if water is hard by using a detergent?

Answer 1:
It is not possible to check if water is hard by using a detergent because detergents are salts of ammonium or sulphonates of long chain carboxylic acids. Unlike soaps they do not react with calcium and magnesium to distinguish nature of water.

Question 2:
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 ?

Answer 2:
It is necessary to agitate to get clean clothes because the soap micelles which entrap oily or greasy particles on the surface of dirty cloth have to be removed from its surface. When the cloth wetted in soap solution is agitated or beaten, the micelles containing oily or greasy dirt get removed from the surface of dirty cloth and go into water and the dirty cloth gets cleaned.

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Exercise Questions (Page 77-78)

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 1:
Ethane, with the molecular formula C2H6 has 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 2:

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 3:
(b) The fuel is not burning completely.

Question 4:
Explain the nature of the covalent bond using the bond formation in CH3Cl

Answer 4:
Carbon can neither lose 4 electrons nor do gain four electrons as these process make the system unstable due to requirement of extra energy. Therefore CH3Cl completes its octet configuration by sharing its 4 electrons with carbon atoms or with atoms of other elements. Hence the bonding that exists in CH3Cl is a covalent bonding.

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.

Question 5:
Draw the electron dot structures for
(a) ethanoic acid
(b) propanone
(c) H2S
(d) F2.

Answer 5:

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Question 6:
What is a homologous series ? Explain with an example.

Answer 6:
A homologous series is a series of compounds, which has the same functional group. This also contains similar general formula and chemical properties. Since there is a change in the physical properties, we can say that there would be an increase in the molecular size and mass.

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 Butane CH3CH2CH2CH3. It can be noticed that there is a difference of −CH2 unit between each successive compound.

Question 7:
How can ethanol and ethanoic acid be differentiated on the basis of their physical and chemical properties?

Answer 7:


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 8:
Micelle formation takes place because of the dirt particles in water and clean water. There are two mediums that are involved: one is pure water and the other being dirt (also called as impurities). The soap also has two mediums:

(i) organic tail and

(ii) ionic head

So the organic tail mixes and dissolves with the dirt whereas the oil or grease and ionic head dissolves and mixes with the water. Therefore, when the material to be cleaned is removed from the water, the dirt is taken off by the soap molecules in the water. Hence, the soap cleans by forming closed structures by the mutual repulsion of the micelles (positively charged heads).

Other solvents such as ethanol, in which sodium salt of fatty acids does not dissolve, so not able to form such micelles.

Question 9:
Why are carbon and its compounds used as fuels for most applications?

Answer 9:
Carbon and its compounds used as fuels for most applications for they have high calorific values and give out a lot of energy. Most of the carbon compounds give a lot of heat and light when burnt in air.

Question 10:
Explain the formation of scum when hard water is treated with soap?

Answer 10:
Scrum is produced from reaction of hard water with soap. Calcium and magnesium present in the hard water form an insoluble precipitate that stick as a white which is also called as scrum.

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Question 11:
What change will you observe if you test soap with litmus paper (red and blue)?

Answer 11:
:When soap is dissolved in water, due to the formation of alkaline NaOH or KOH, the solution is alkaline. The solution changes the colour of the red litmus to blue, but in the soap solution, the blue litmus remains blue.

Question 12:
What is hydrogenation? What is its industrial application?

Answer 12:
Hydrogenation is a process or a chemical reaction between hydrogen and other compounds. It is usually done in the presence of catalysts: for example nickel, palladium or platinum. Hydrogenation is used mainly to saturate organic compounds.

Question 13:
Which of the following hydrocarbons undergo addition reactions: C2H6, C3H8, C3H6, C2H2 and CH4?

Answer 13:
Unsaturated hydrocarbons undergo addition reactions. C3H6 and C2H2 are unsaturated hydrocarbons which undergo addition reactions.

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

Answer 14:
Butter is a saturated carbon compound while cooking oil is an unsaturated carbon compound. An unsaturated compound decolourises bromine water, while a saturated compound cannot decolourise it. So we can distinguish chemically between a cooking oil and butter by the bromine water. Add bromine water to a little of cooking oil and butter taken in separate test-tubes.

  • Cooking oil decolourises bromine water showing that it is an unsaturated compound.
  • Butter does not decolourise bromine water showing that it is a saturated compound

Question 15:
Explain the mechanism of the cleaning action of soaps.

Answer 15:
When a dirty cloth is put in water containing dissolved soap, then the hydrocarbon end of the soap molecules in micelle attach to the oil or grease particles present on the surface of dirty cloth. In this way the soap micelle entraps the oily or greasy particles by using its hydrocarbon ends. The ionic ends of the soap molecules in the micelles, however, remain attached to water. When the dirty cloth is agitated in soap solution, the oily and greasy particles present on its surface and entrapped by soap micelles get dispersed in water due to which the soap water becomes dirty but the cloth gets cleaned. The cloth is cleaned thoroughly by rinsing in clean water a number of times.


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