NCERT Solution Science Class 10 Chapter 4 Carbon and its Compounds
NCERT Solution Science Class 10 Chapter 4 Carbon and its Compounds all questions and answers. Science Class 10 4th Chapter Carbon and its Compounds exercise solution and experts answer. As one of online learning platforms, we (netex.) are excited to offer the NCERT Solution Science Class 10 Chapter 4. This solution is designed to help students who are looking to brush up on their Science concepts on Chapter 4 Carbon and its Compounds.
Page 61:
1.) What would be the electron dot structure of carbon dioxide which has the formula CO2 ?
Ans 1- In CO2, the two oxygen is bonded by double bonds with carbon.
Electron dot structure-
2.) 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.)
Ans 2- S8 molecule of a Sulphur forms a ring like structure.
Electron dot structure-
Page no. 68
1.) How many structural isomers can you draw for pentane?
Ans 1 – Pentane has 3 isomers:
2.) What are the two properties of carbon which lead to the huge number of carbon compounds we see around us?
Ans 2- The two properties of carbon are:
i) Catenation- Carbon has the ability to form long chains with other atoms of carbon by single, double or triple bonds.
ii) Tetravalency: As carbon has a valency of four, so it is capable of bonding with other four atoms of carbon or any other four mono- valent atoms.
3.) What will be the formula and electron dot structure of cyclopentane?
Ans 3- Cyclopentane is a cyclic compound of five carbon.
Formula: C5H10
Electron dot structure:
4) Draw the structures for the following compounds. (i) Ethanoic acid (ii) Bromopentane* (iii) Butanone (iv) Hexanal.
*Are structural isomers possible for bromopentane?
Ans 4- Yes, 3 structural isomers are possible for Bromopentane depending upon the position of Bromine.
5.) How would you name the following compounds?
(i) CH3—CH2—Br
Ans 5- i) Bromoethane
Reason: Two carbon atoms, so ethane and bromine is attached. Therefore, bromo prefix is used.
H2-C=O
ii) Answer:
Methanal
Reason: One carbon atom and aldehyde group is attached. Therefore, suffix ‘al’ is used.
CH3-CH2-CH2-CH2-C≡CH
iii) Answer:
Hex- 1- yne
Reason: 6 carbon atoms, so hex word is used and 1 triple bond is present. Therefore, the suffix ‘yne’ is used.
Page no: 71
1.) Why is the conversion of ethanol to ethanoic acid an oxidation reaction?
Ans1- The conversion of ethanol to ethanoic acid is an oxidation reaction as one oxygen is added to ethanol in the presence of an oxidising agent such as Alkaline potassium permanganate or acidified potassium dichromate.
Reaction: CH3-CH2-OH + Alk. KMnO4 gives CH3COOH + H2O
2.) A mixture of oxygen and ethyne is burnt for welding. Can you tell why a mixture of ethyne and air is not used?
Ans 2- Ethyne being an unsaturated carbon contains high carbon content. The burning of ethyne in presence of air gives sooty flame with less amount of heat is produced due to the incomplete combustion. The low temperatures is not sufficient for welding. Therefore, ethyne is burnt in pure oxygen to produce sufficient heat( high temp.) for welding.
Page no: 74
1.) How would you distinguish experimentally between an alcohol and a carboxylic acid?
Ans 1- Two test can be done to distinguish between an alcohol and a carboxylic acid.
i) Litmus test- If blue litmus paper turns into red, then it is a carboxylic acid and if it does not change the colour then it is an alcohol.
ii) Sodium bicarbonate test – When sodium bicarbonate is added to a given compound, there is brisk effervescence i.e the evolution of Carbon dioxide gas (colourless) which turns lime water milky and hence it will be carboxylic acid. No effervescence then it is an alcohol.
2.) What are oxidising agents?
Ans 2 – The agents which adds oxygen in the oxidation reaction are called oxidizing agent.
E.g.: Alkaline potassium permanganate (KMnO4) and acidified potassium dichromate (K2Cr2O7)
Page no: 76
1.) Would you be able to check if water is hard by using a detergent?
Ans1 – No, we cannot check the water is hard or not by using detergent.
Detergent is used to remove the hardness of water.
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?
Ans 2- Agitation is necessary to clean the clothes because the soap micelles trapped the dirty particles on the surface of clothes. By agitation the dirt can be removed from the surface of clothes.
Exercise
1.) Ethane, with the molecular formula C2H6 has
(a) 6 covalent bonds.
(b) 7 covalent bonds.
(c) 8 covalent bonds.
(d) 9 covalent bonds.
Ans1- b) 7 Covalent bonds
Reason: 1 bond with carbon- carbon and 6 bonds with carbon- hydrogen
2.) Butanone is a four-carbon compound with the functional group
(a) carboxylic acid.
(b) aldehyde.
(c) ketone.
(d) Alcohol
Ans2- c) Ketone
Reason- The suffix used is ‘one’ i.e ketone group
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.
Ans 3- b) the fuel is not burning completely
Reason- Some carbon particles does not oxidised and thus form soot. The soot gets deposited at the bottom of vessels which is black in colour.
4.) Explain the nature of the covalent bond using the bond formation in CH3Cl.
Ans 4- Covalent bonds are formed by the sharing of electrons between the atoms. Here, the compound CH3Cl forms 4 covalent bonds. The carbon need four electrons to complete its octet. Therefore, electrons are shared between four atoms. The hydrogen need one electron to complete its duplet and chlorine need one electrons to complete its octet.
Alternative Answer –
CH3Cl in this there are three atoms, carbon, hydrogen and chlorine. First we notice the carbon it has four single covalent bonds and Hydrogen one valence electron and chlorine has seven valence electrons in this CH3Cl. We know that carbon has four single covalent bonds in which three are connected with hydrogen to form single bond in each and chlorine has seven covalent electrons in that carbon will form one bond with chlorine to make chlorine as octet. In other words carbon shared it’s bond with three hydrogen atom and one chlorine atom to form CH3Cl.
5.) Draw the electron dot structures for
(a) ethanoic acid.
(b) H2 S.
(c) propanone.
(d) F2 .
Ans –
(a) ethanoic acid.
In case you are missed :- Previous Chapter Solution
6.) What is an homologous series? Explain with an example.
Ans 6- A series of compounds having same functional group and similar chemical properties is called as homologous series. The two adjacent members are differ by CH2 unit.
Example- methanoic acid, ethanoic acid, propanoic acid, butanoic acid etc. all have same functional group i.e carboxylic acid group & hence similar chemical properties.
Alternative Answer –
In an Carbon chain contain the same functional group with hydrogen in a same general formula is known as homologous series.
Examples from Alkane group
CH4 – Methane. C2H6 – Ethane
C4H10 – Butane. C3H8 – Propane
C6H14 – Hexane.
Above examples show that the alkanes like methane ethane etc are same functional group with hydrogen in a same general formula CnH2n+2
And we can notice that the difference between each successive compound is -CH2
For example CH4 and C2H6 the difference between these two components is -CH2 units.
7.) How can ethanol and ethanoic acid be differentiated on the basis of their physical and chemical properties?
Ans7-
Ethanol |
Ethanoic acid |
It is liquid at room temperature with a pleasant smell. |
It has a melting point of 17°c i.e below it room temperature. It freezes out in winter. |
It does not reacts with NaOH. |
It reacts with NaOH and form sodium ethanoate and water. |
It does not react with carbonates and bicarbonates. |
It reacts with bicarbonates and forms salt, CO2 and water. |
Alternative Answer –
Physical properties
Ethanol | Ethanoic acid |
1. Ethanol has boiling point 351 K. | Ethanoic acid has boiling point 391 k. |
2. Ethanol does not freez in winter time. | Ethanoic acid freez in winter time at 17° C. |
3. Ethanol has sweet odour. | Ethanoic acid has pungent odour. |
4. Ethanol has melting point 156 K. | Ethanoic acid has melting point 290K |
Chemical properties
Ethanol | Ethanoic acid |
1. It does not produce carbon dioxide gas. | When ethanoic acid react with sodium after the reaction it will gives carbon dioxide gas. |
2. It does not react with litmus paper. | It react with litmus paper and it turns blue litmus to red litmus. |
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?
Ans 8- Soap are the long fatty acid chains of sodium and potassium. Soap consist of two group namely hydrophilic (affinity for water) and hydrophobic end. So when soap is dissolved in water the hydrophilic end gets dissolved in water and the hydrophobic end towards oil, dirt. Thus, forming the structure of micelle. When we rinse away the clothes the hydrophobic end remains in water and acts as a colloids.
Micelle formation will not take place in ethanol instead of water because ethanol is hydrocarbon molecule, so, the hydrophobic end of soap will get dissolved in alcohol.
Alternative Answer –
We know that soap is used to clean the dirt and oil,because oil is not disolve in water but soap can disolve oil and dirt because it contains sodium or potassium salts of long chain carboxylic acids. When soap is in contact of water then it forms micelles and each micelle contains two ends in which one is hydrophilic end and another one is hydrophobic end in that hydrophilic end is attract the water whereas another one is hydrophobic which is repelling the water which forms emulsion in water so that soap will helps the clean dirt.
We know that soap contains sodium or potassium salts of long chain carboxylic acid which react with water and form micelle but other solvent like ethanol, these potassium or sodium salts of long chain of carboxylic acids does not disolve or hydrophobic. In this reason other solvents such as ethanol does not form micelles.
9.) Why are carbon and its compounds used as fuels for most applications?
Ans 9- Carbon and its compounds are used as a fuel because of their high calorific value, production of large amount of heat and light when burnt in presence of air(combustion).
Alternative Answer –
When carbon is react with oxygen it will gives carbon dioxide with light and heat. Most of the carbon compounds are produced high with light on burning,in this reason carbon and its Compounds are used as fuel for most applications. Here are the some reactions which shows that carbon and its Compounds when react with oxygen and it gives large amount of heat and light.
- CH4 + O2 → CO2 + H2O + heat and light
- C + O2 → CO2 + heat and light
- CH3CH2OH + O2 → CO2 + H2O + heat and light
10.) Explain the formation of scum when hard water is treated with soap.
Ans 10- Hard water consist of salts of calcium and magnesium. Soap contains long fatty acids chain of salt sodium and potassium. When soap is treated with hard water the calcium and magnesium react with soap and form a precipitate of white layer called as scum.
Alternative Answer –
When soap is react with calcium and magnesium salts which is present in hard water then after reaction a white lyare of foam will be formed on the surface of the water it is called scum, which causes the hardness of water and when scum will be formed the soap will loose its strength of cleaning so to solve this problem we use large amount of soap or detergent as cleaning agent.
11.) What change will you observe if you test soap with litmus paper (red and blue)?
Ans 11- Soap is basic in nature. Therefore, it turns blue litmus blue and red litmus blue.
Alternative Answer –
Soap is an sodium or potassium salts of long chain carboxylic acids. And most of soap are have their pH value about 9-10 which represents that soap is an basic in nature, therefore when we use blue litmus we can see there is no change in litmus paper where as when we use red litmus on soap it will turns red litmus to blue which shows that soap is basic in nature.
12.) What is hydrogenation? What is its industrial application?
Ans 12- Unsaturated hydrocarbon are converted into saturated hydrocarbon under the addition reaction by using nickel, palladium as a catalyst is called as hydrogenation reaction.
- Industrial application-
i) Hydrogenation of vegetable oils using a nickel catalyst. As they contains long unsaturated carbon chains.
Alternative Answer –
An chemical procedure which is in presence of catalyst such as palladium or nickel when unsaturated hydrocarbons are added with hydrogen after reaction it will gives saturated hydrocarbons this process is known as hydrogenation.
Normally in industrial level vegetable oil has long unsaturated hydrocarbons chain they add hydrogen in presence of catalyst as nickel to make vegetable oil as saturated hydrocarbon.
13.) Which of the following hydrocarbons undergo addition reactions: C2H6 , C3H8 , C3H6 , C2H2 and CH4 .
Ans 13 – Unsaturated hydrocarbon undergoes addition reaction I.e C3H6 & C2H2. Whereas CH4, C2H6 and C3H8 are saturated in nature and will not undergo addition reaction.
Alternative Answer –
C3H6 and C2H2 these two hydrocarbons are undergo the addition reactions.
14.) Give a test that can be used to differentiate between saturated and unsaturated hydrocarbons.
Ans 14- Butter consist of saturated fats. So it will not show hydrogenation reaction. But oils contains unsaturated fats. They undergoes addition reaction or hydrogenation reaction.
Alternative Answer –
We can use Bromine water test, for this experiment first we have two test tubes in which one contain saturated hydrocarbon and another contains unsaturated hydrocarbon and next we add Bromine water into both test tube and after the chemical reaction we can notice that the test tube which contains unsaturated hydrocarbon is change its colour that means bromine water colour which is red brown after the reaction it will become colourless and another test tube which contains saturated hydrocarbon does not change any colour and it look like same colour of bromine water that is red brown.
15.) Explain the mechanism of the cleaning action of soaps.
Ans15- The dirt present on clothes contains organic molecule. So it cannot be removed by only washing with water. To remove dirt we add soap in water which contains two end one is hydrophilic(water lover) and other one is hydrophobic end (away from water). So the hydrophilic part dissolve in water and the hydrophobic end gets attached with dirt. Thus, they arranged themselves in the structure of micelles. The dirt gets trap at the centre due to micelles. So, when we rinse away the clothes the dirt get suspended in the water.
Alternative Answer –
We know that normal water has no power to clean dirt and oil, to clean oil and dirt we use soap. Soap is an sodium or potassium salts of long chain carboxylic acid the soap contains micelles, each Micelle has two ends in which one is hydrophilic which interacts with water and another one is hydrophobic which interact with hydrocarbon. The soap micelles are helps the pulling out the dirt in water. That’s why we use soap as cleaning agent.
Also see: Videos on Carbon and its compounds
Important Faq
Q. What are the important keywords of the chapter Carbon and its Compounds Class 10?
Ans. Students need to clear concept on the keywords i.e. Covalent Bonds, Nature of Carbon, Saturated and Unsaturated Carbon Compounds, Homologous Series, Nomenclature of Carbon Compounds, Combustion, Carbon Compounds.
Q. How can i clear concept on the chapter Carbon and its Compounds?
Ans. You can clear concept from this page and also from videos on Carbon Compounds, Combustion, Carbon Compounds.
In case you are missed :- Next Chapter Solution