NCERT Exemplar Solutions Class 10 Science Carbon and Its Compounds

Read NCERT Exemplar Solutions Class 10 Science Science Carbon and its Compounds below, students should study NCERT Exemplar class 10 Science available on Studiestoday.com with solved questions and answers. These chapter wise answers for class 10 Science Exemplar problems have been prepared by teacher of Grade 10. These NCERT Exemplar class 10 Science solutions have been designed as per the latest NCERT syllabus for class 10 and if practiced thoroughly can help you to score good marks in standard 10 Science class tests and examinations

Multiple Choice Questions..............


Question 1:  Carbon exists in the atmosphere in the form of

(a) carbon monoxide only

(b) carbon monoxide in traces and carbon dioxide

(c) carbon dioxide only

(d) coal 

Solution 1: (c) carbon-dioxide only

Carbon exists in the atmosphere in the form of carbon-dioxide.

 

Question 2: Which of the following statements are usually correct for carbon compounds? These

(i) are good conductors of electricity

(ii) are poor conductors of electricity

(iii) have strong forces of attraction between their molecules

(iv) do not have strong forces of attraction between their molecules

(a) (i) and (iii)

(b) (ii) and (iii)

(c) (i) and (iv)

(d) (ii) and (iv) 

Solution 2:  (d) (ii) and (iv) 

Since carbon compounds form covalent bonds, they have a very weak attraction. Carbon compounds are weak electrical conductors.

 

Question 3:  A molecule of ammonia (NH3) has

(a) only single bonds

(b) only double bonds

(c) only triple bonds

(d) two double bonds and one single bond 

Solution 3: (a) only single bonds

Three hydrogen atoms combine with one nitrogen atom to form ammonia, which has three electrons in its outermost shell. There are single-issue bonds.

 

Question 4: Buckminsterfullerene is an allotropic form of

(a) phosphorus

(b) sulphur

(c) carbon

(d) tin 

Solution 4: (c) carbon 

These are the allotropes of carbon: 

Diamond, Graphite, Lonsdaleite, C60 (Buckminsterfullerene or buckyball), C540, C70, Amorphous carbon, and a single-walled carbon nanotube, or buckytube.

 

Question 5:  Which of the following are correct structural isomers of butane? 

NCERT Exemplar Solutions Class 10 Science Carbon and its Compounds

(a) (i) and (iii)

(b) (ii) and (iv)

(c) (i) and (ii)

(d) (iii) and (iv) 

Solution 5:  (c) (i) and (ii) 

Chemical formula of Butane isC4H10, here option iii) and iv) have 8 hydrogen atoms, hence they are wrong.


Question 6: CH3 – CH2 – OH Alkaline KMnO Heat  + → CH3 – COOH

In the above-given reaction, alkaline KMnO4 acts as

(a) reducing agent

(b) oxidising agent

(c) catalyst

(d) dehydrating agent 

Solution 6: (b) oxidising agent

The oxidation of ethanol occurs when two hydrogen atoms are replaced by an oxygen atom. Potassium is used to provide oxygen in this situation.

 

Question 7:  Oils on treating with hydrogen in the presence of palladium or nickel catalyst form fats. This is an example of

(a) Addition reaction

(b) Substitution reaction

(c) Displacement reaction

(d) Oxidation reaction 

Solution 7:  (a) Addition reaction

It is an addition reaction when hydrogen is added to oil. 

 

Question 8:  In which of the following compounds, — OH is the functional group?

(a) Butanone

(b) Butanol

(c) Butanoic acid

(d) Butanal 

Solution 8:  (b) Butanol 

Make a compound with OH. Since all functional classes have the suffix ol, the correct answer is (b) Butanol.

 

Question 9:  The soap molecule has a

(a) hydrophilic head and a hydrophobic tail

(b) hydrophobic head and a hydrophilic tail

(c) hydrophobic head and a hydrophobic tail

(d) hydrophilic head and a hydrophilic tail 

Solution 9:  (a) hydrophilic head and a hydrophobic tail

Due to the hydrophobic tail within a micelle, oil and grease are trapped. The micelle's outer surface is made up of hydrophobic heads. As a result, micelle is quickly washed away by spray.

 

Question 10: Which of the following is the correct representation of the electron dot structure of nitrogen?

NCERT Exemplar Solutions Class 10 Science Carbon and its Compounds

Solution 10:  (d)

In this configuration, nitrogen atoms receive 8 electrons, although this is not the case in other structures.

 

Question 11:  Structural formula of ethyne is

NCERT Exemplar Solutions Class 10 Science Carbon and its Compounds

Solution 11: (a)

Ethyne's chemical formula is C2H2, so the response is (a).

 

Question 12:  Identify the unsaturated compounds from the following

(i) Propane

(ii) Propene

(iii) Propyne

(iv) Chloropropane

(a) (i) and (ii)

(b) (ii) and (iv)

(c) (iii) and (iv)

(d) (ii) and (iii) 

Solution 12:  (d) (ii) and (iii) 

Propyne has a triple bond, while propene has a double bond. As a consequence, they're unsaturated compounds.

 

Question 13:  Chlorine reacts with saturated hydrocarbons at room temperature in the

(a) absence of sunlight

(b) presence of sunlight

(c) presence of water

(d) presence of hydrochloric acid 

Solution 13: (b) presence of sunlight

Chlorine interacts with hydrocarbons and displaces hydrogen atoms when exposed to sunlight.

 

Question 14: In the soap micelles

(a) the ionic end of soap is on the surface of the cluster while the carbon chain is in the interior of the cluster.

(b) ionic end of soap is in the interior of the cluster and the carbon chain is out of the cluster.

(c) both ionic end and carbon chain are in the interior of the cluster

(d) both ionic end and carbon chain are on the exterior of the cluster 

Solution 14:  (a) the ionic end of soap is on the surface of the cluster while the carbon chain is in the interior of the cluster. 

In soap solution, a micelle is a spherical aggregate of soap molecules. The ionic end of soap is on the surface of the cluster, while the carbon chain is within the cluster in soap micelles.

 

Question 15:  Pentane has the molecular formula C5 H12. It has

(a) 5 covalent bonds

(b) 12 covalent bonds

(c) 16 covalent bonds

(d) 17 covalent bonds 

Solution 15:  (c) 16 covalent bonds

Pentane has the molecular formula C5H12. It has 16 covalent bonds.

 

Question 16:  Structural formula of benzene is

NCERT Exemplar Solutions Class 10 Science Carbon and its Compounds

Solution 16:  (c) 

C6H6 is the molecular formula for benzene. Since the arms of carbon atoms are occupied in choice call, it is the correct response.

 

Question 17:  Ethanol reacts with sodium and forms two products. These are

(a) sodium ethanoate and hydrogen

(b) sodium ethanoate and oxygen

(c) sodium ethoxide and hydrogen

(d) sodium ethoxide and oxygen 

Solution 17:  (c) sodium ethoxide and hydrogen

Ethanol reacts with sodium and forms two products: 2Na + 2CH3CH2OH → 2CH3CH2ONa + H2

 

Question 18:  The correct structural formula of butanoic acid is

NCERT Exemplar Solutions Class 10 Science Carbon and its Compounds

Solution 18: (d)

NCERT Exemplar Solutions Class 10 Science Carbon and its Compounds


Question 19: Vinegar is a solution of

(a) 50% – 60% acetic acid in alcohol

(b) 5% – 8% acetic acid in alcohol

(c) 5% – 8% acetic acid in water

(d) 50% – 60% acetic acid in water 

Solution 19:  (c) 5% – 8% acetic acid in water

 

Question 20:  Mineral acids are stronger acids than carboxylic acids because

(i) mineral acids are completely ionised

(ii) carboxylic acids are completely ionised

(iii) mineral acids are partially ionised

(iv) carboxylic acids are partially ionised

(a) (i) and (iv)

(b) (ii) and (iii)

(c) (i) and (ii)

(d) (iii) and (iv) 

Solution 20:  (a) (i) and (iv)

Carboxylic acids are partly ionised, while mineral acids are fully ionised. As a result, mineral acids are more active than carboxylic acids.

 

Question 21:  Carbon forms four covalent bonds by sharing its four valence electrons with four univalent atoms, e.g. hydrogen. After the formation of four bonds, carbon attains the electronic configuration of

(a) helium

(b) neon

(c) argon

(d) krypton 

Solution 21:  (b) neon

After four valence electrons were shared with univalent atoms. Carbon's electronic configuration becomes 2.8, which is the same as Neon's electronic configuration.

 

NCERT Exemplar Solutions Class 10 Science Carbon and its Compounds

 

Question 24:  Which among the following are unsaturated hydrocarbons?

NCERT Exemplar Solutions Class 10 Science Carbon and its Compounds

(a) (i) and (iii)

(b) (ii) and (iii)

(c) (ii) and (iv)

(d) (iii) and (iv) 

Solution 24:  (c) (ii) and (iv)

Option (ii) and (iv) are unsaturated hydrocarbons since they have double and triple bonds.

 

Question 25:  Which of the following does not belong to the same homologous series?

(a) CH4

(b) C2 H6

(c) C3 H8

(d) C4 H8 

Solution 25: (d) C4 H8 

CnH2n is the general formula for C4H8, and CnH2n + 2 is the formula for other options.

 

Question 26:  The name of the compound CH3 — CH2 — CHO is

(a) Propanal

(b) Propanone

(c) Ethanol

(d) Ethanal 

Solution 26:  (a) Propanal 

This compound has three carbon atoms and an aldehyde, which gives it the suffix al.

 

Question 27:  The heteroatoms present in CH3 — CH2 — O — CH2— CH2 Cl are

(i) oxygen

(ii) carbon

(iii) hydrogen

(iv) chlorine

(a) (i) and (ii)

(b) (ii) and (iii)

(c) (iii) and (iv)

(d) (i) and (iv) 

Solution 27: (d) (i) and (iv)

Oxygen and chlorine are heteroatoms since they are not basic components of hydrocarbons.

 

Question 28:  Which of the following represents the saponification reaction?

(a) CH3COONa + NaOH CH4 + Na2CO3

(b) CH3COOH + C2H5OH CH3 COOC2H5 +H2O

(c) 2CH3COOH + 2Na → 2CH3COONa + H2

(d) CH3COOC2H5 + NaOH → CH3COONa + C2H5OH 

Solution 28:  (d) CH3COOC2H5 + NaOH → CH3COONa + C2H5OH  

Saponification is a reaction in which an ester is treated with an alkali to create ethanol and sodium ethanoate.

 

Question 29:  The first member of the alkyne homologous series is

(a) ethyne

(b) ethene

(c) propyne

(d) methane 

Solution 29:  (b) ethene 

Ethene is the first member of the alkyne homologous series.

 

Short Answer Questions...........................


Question 30:  Draw the electron dot structure of ethyne and also draw its structural formula 

Solution 30:   

Molecular formula of ethyne is C2H2.

Electronic Formula of ethyne is

 NCERT Exemplar Solutions Class 10 Science Carbon and its Compounds

 

Question 31:  Write the names of the following compounds.

  NCERT Exemplar Solutions Class 10 Science Carbon and its Compounds

Solution 31:

(a) Pentanoic acid

(b) Butyne

(c) Heptanal

(d) Pentanol

 

Question 32: Identify and name the functional groups present in the following compounds.

NCERT Exemplar Solutions Class 10 Science Carbon and its Compounds

Solution 32:

(a) Alcohol

(b) Carboxylic acid

(c) Ketone

(d) Alkene

 

Question 33:  A compound X is formed by the reaction of a carboxylic acid C2H4O2 and an alcohol in the presence of a few drops of H2SO4. The alcohol on oxidation with alkaline KMnO4 followed by acidification gives the same carboxylic acid as used in this reaction. Give the names and structures of (a) carboxylic acid, (b) alcohol and (c) the compound X. Also write the reaction. 

Solution 33:

(a) Carboxylic acid

NCERT Exemplar Solutions Class 10 Science Carbon and its Compounds

 

Question 34:  Why detergents are better cleansing agents than soaps? Explain. 

Solution 34:   Since detergents are ammonium or sulphonate salts of long-chain carboxylic acids, they are better than soaps. With calcium and magnesium present in hard water, the charged ends of theses will not precipitate. Soaps, on the other hand, will precipitate with the calcium and magnesium ions in hard water.


Question 35:  Name the functional groups present in the following compounds.

(a) CH3COCH2 CH2 CH2 CH3

(b) CH3CH2CH2COOH

(c) CH3CH2 CH2 CH2 CHO

(d) CH3CH2OH 

Solution 35: 

(a) Ketone is the functional group present in CH3COCH2 CH2 CH2 CH3.

(b) Carboxylic acid is the functional group present in CH3CH2CH2COOH.

(c) Aldehyde is the functional group present in CH3CH2 CH2 CH2 CHO.

(d) Alcohol is the functional group present in CH3CH2OH.

 

Question 36:  How is ethene prepared from ethanol? Give the reaction involved in it. 

Solution 36:   Ethene is made by heating Ethanol with excess of concentrated sulphuric acid at 443k.

                          Conc H2SO4

CH3-CH2OH ——————→CH2=CH2 + H2O

   (ethanol)                               (ethene)     (water) 

 

Question 37:  Intake of a small quantity of methanol can be lethal. Comment. 

Solution 37:   Methanol is converted to methane in the liver, which destroys all cells. Methanol also damages the optic nerves, resulting in blindness. As a result, even a small amount of methanol can be fatal.

 

Question 38:  A gas is evolved when ethanol reacts with sodium. Name the gas evolved and also write the balanced chemical equation of the reaction involved. 

Solution 38:   When ethanol reacts with sodium it gives Sodium ethoxide with the liberation of hydrogen gas.

NCERT Exemplar Solutions Class 10 Science Carbon and its Compounds

 

Question 39:  Ethene is formed when ethanol at 443 K is heated with excess of concentrated sulphuric acid. What is the role of sulphuric acid in this reaction? Write the balanced chemical equation of this reaction. 

Solution 39:  In the formation of ethene, sulphuric acid serves as a catalyst and a dehydrating agent.

 

Question 40:  Carbon, Group (14) element in the Periodic Table, is known to form compounds with many elements. Write an example of a compound formed with:

(a) chlorine (Group 17 of Periodic Table)

(b) oxygen (Group 16 of Periodic Table) 

Solution 40:

a) Carbon Tetrachloride - CCl4 of group 17 of periodic table.

b) Carbon-dioxide - CO2 of group16 of periodic table.

 

Question 41:  In electron dot structure, the valence shell electrons are represented by crosses or dots.

(a) The atomic number of chlorine is 17. Write its electronic configuration.

(b) Draw the electron dot structure of chlorine molecule. 

Solution 41:  (a) Atomic number of chlorine is 17. So its electronic configuration would be 2 atoms in K shell, 8 atoms in L shell, 7 atoms in M shell.

 NCERT Exemplar Solutions Class 10 Science Carbon and its Compounds

 

Question 42:  Catenation is the ability of an atom to form bonds with other atoms of the same element. It is exhibited by both carbon and silicon. Compare the ability of catenation of the two elements. Give reasons. 

Solution 42:   Silicon and Carbon both exhibit catenation. Since silicon bonds are less stable and reactive, whereas carbon bonds are extremely solid, carbon exhibits better catenation than silicon.

 

Question 43:  Unsaturated hydrocarbons contain multiple bonds between the two C-atoms and show addition reactions. Give the test to distinguish ethane from ethene. 

Solution 43:   Non-saturated hydrocarbons produce a yellow flame and a lot of soot, while saturated hydrocarbons produce a clean flame and no soot. Ethane is a saturated hydrocarbon that burns cleanly and produces no soot. Since ethene is unsaturated, it produces a yellow flame that produces a lot of soot.

 

NCERT Exemplar Solutions Class 10 Science Carbon and its Compounds

 

Question 45:  Write the structural formulae of all the isomers of hexane. 

Solution 45:

NCERT Exemplar Solutions Class 10 Science Carbon and its Compounds


Question 46:  What is the role of metal or reagents written on arrows in the given chemical reactions? 

Solution 46:

NCERT Exemplar Solutions Class 10 Science Carbon and its Compounds



Question 47:  A salt X is formed and a gas is evolved when ethanoic acid reacts with sodium hydrogen carbonate. Name the salt X and the gas evolved. Describe an activity and draw the diagram of the apparatus to prove that the evolved gas is the one which you have named. Also, write a chemical equation of the reaction involved. 

Solution 47:  When ethanoic acid reacts with sodium hydrogen carbonate, Sodium Ethanoate is formed, and carbon dioxide gas is produced.

CH3COOH + NaHCO3 → CH3COONa + H2O + CO2

The salt X in this case is Sodium Ethanoate, and the gas produced is Carbon-dioxide.

 NCERT Exemplar Solutions Class 10 Science Carbon and its Compounds

 

Description of Activity:

• Assemble the experiment as shown in the diagram.

• In a test tube, put a spoonful of Sodium Hydrogen Carbonate and 2ml of dilute ethanoic acid.

• In the test tube, there is a lot of effervescence.

• Splash the gas emitted into lime water.

• Lime water turns milky, indicating CO2 evolution.

 

Question 48:

(a) What are hydrocarbons? Give examples.

(b) Give the structural differences between saturated and unsaturated hydrocarbons with two examples each.

(c) What is a functional group? Give examples of four different functional groups. 

Solution 48:

(a) Hydrocarbons are carbon and hydrogen-based compounds. Ethane and methane are two examples.

(b) In saturated hydrocarbons, all bonds are single bonds, while in unsaturated hydrocarbons, all bonds are double or triple bonds.

Examples of saturated hydrocarbon are Ethane, Methane, Propane

Examples of unsaturated hydrocarbons are Ethyne, Ethene, Propene 

(c) Functional groups are made up of atoms that are linked in a particular way and are responsible for the compound's chemical properties. CHO stands for aldehyde, OH for hydroxyl, and COOH for carboxylic acid.

 

Question 49:  Name the reaction which is commonly used in the conversion of vegetable oils to fats. Explain the reaction involved in detail. 

Solution 49:   The conversion of oils to fats involves the addition reaction. Hydrogenation is the name for this operation. Unsaturated vegetable fats are converted to saturated fats with saturated carbons in this process.

In the hydrogenation process, nickel is used as a catalyst, and the reaction is shown below.

NCERT Exemplar Solutions Class 10 Science Carbon and its Compounds


Question 50:  

(a) Write the formula and draw the electron dot structure of carbon tetrachloride.

(b) What is saponification? Write the reaction involved in this process. 

Solution 50:

(a) Formula of Carbon tetrachloride is CCl4.

 NCERT Exemplar Solutions Class 10 Science Carbon and its Compounds 

(b) Saponification is the process of reacting an ester with a base to produce a sodium salt of carboxylic acid and alcohol, which is used to make soap.

CH3COOC2H5 + NaOH CH3 COONa + C2H5OH

 

Question 51:  Esters are sweet-smelling substances and are used in making perfumes. Suggest some activity and the reaction involved in the preparation of an ester with well-labelled diagram. 

Solution 51:   1 mL ethanol, 1 mL glacial acetic acid, and a few drops of concentrated H2SO4 in a test tube Warm the test tube in a water bath for 5 minutes. Fill a beaker halfway with the contents. Ester's creation is confirmed by its sweet odour.

NCERT Exemplar Solutions Class 10 Science Carbon and its Compounds


Question 52:  A compound C (molecular formula, C2H4O2) reacts with Na – metal to form a compound R and evolves a gas which burns with a pop sound. Compound C on treatment with an alcohol A in presence of an acid forms a sweet-smelling compound S (molecular formula, C3H6O2). On addition of NaOH to C, it also gives R and water. S on treatment with NaOH solution gives back R and A. Identify C, R, A, S and write down the reactions involved. 

Solution 52:

(a) Ethanoic acid [Acetic acid] is Compound C.

It forms the compound R when it reacts with sodium metal. 

(b) Sodium Ethanoate is represented by the letter R.

2CH3COOH + 2Na → 2CH3COONa + H2

(In the presence of Concentrated H2SO4

(c) CH3COOH + C2H5OH → CH3COOC2H5 + H20

As a result, compound S stands for Ester or Ethyl Ethanoate, and compound A stands for Ethanol. 

(d) CH3COOC2H5 + NaoH → CH3COONa + C2H5OH.

So, compound R is Sodium Ethanoate. 

So compound C indicates Ethanoic acid.

Compound A represents Ethanol.

Compound S indicates Ester and R sodium Ethanoate.

 

Question 53:  Look at the given figure and answer the following questions.

(a) What change would you observe in the calcium hydroxide solution taken in tube B?

(b) Write the reaction involved in test tubes A and B respectively.

(c) If ethanol is given instead of ethanoic acid, would you expect the same change?

(d) How can a solution of lime water be prepared in the laboratory?

NCERT Exemplar Solutions Class 10 Science Carbon and its Compounds


Solution 53:

(a) Calcium Hydroxide solution in test tube B will turn milky. 

(b) Reaction involved in test tubes A:

CH3COOH + NaHCO3 → CH3COONa + CO2 + H2O

Reaction involved in test tube B:

Ca(OH)2 + CO2 CaCO3 + H2

(c) Sodium Hydrogen Carbonate does not react with ethanol. As a result, the same improvement will not be noticed. 

(d) Fill a beaker halfway with distilled water, then add the calcium carbonate powder and stir well. Allow the solution to settle before separating the clear solution from the lime water.

 

Question 54:  How would you bring about the following conversions? Name the process and write the reaction involved.

(a) ethanol to ethene.

(b) propanol to propanoic acid. Write the reactions. 

Solution 54:

(a) Ethene is formed when ethanol is heated at 443 K with an excess of concentrated sulphuric acid.

CH3CH2OH Con H2SO4 CH2 = CH + H2

(b) Propanoic acid is made by treating propanol with alkaline potassium permanganate or acidified potassium-di-chromate.

CH3CH2CH2OH Alk KMnO4/ acidified K2Cr2O7 CH3CH2COOH

 

Question 55:  Draw the possible isomers of the compound with molecular formula C3H6O and also give their electron dot structures. 

Solution 55:

NCERT Exemplar Solutions Class 10 Science Carbon and its Compounds


Question 56:  Explain the given reactions with the examples

(a) Hydrogenation reaction

(b) Oxidation reaction

(c) Substitution reaction

(d) Saponification reaction

(e) Combustion reaction 

Solution 56:

(a) In the presence of a catalyst, a hydrogenation reaction is known as an addition reaction between hydrogen and other compounds.

CH2 = CH2 → CH3CH3 

(b) An oxidation reaction occurs when oxygen reacts with another element or compound. To put it another way, it's when a molecule loses its electrons.

2Mg + O2 → 2MgO 

(c) A substitution reaction occurs when a more reactive element dispenses with a less reactive element from its aqueous salt solution.

Zn + CuSO4 → ZnSO4 + Cu 

(d) The saponification reaction occurs when an ester is hydrolyzed with NaOH or KOH to produce alcohol and the sodium or potassium salt of the acid.

CH3COOC2H5 + NaOH → C2H5OH + CH3COONa 

(e) The combustion reaction occurs when oxygen reacts with a compound to produce carbon dioxide and water. These are exothermic reactions, which means they produce heat.

CH4 + 2O2 → 2H2O + CO2

  

Question 57:  An organic compound A on heating with concentrated H2SO4 forms a compound B which on addition of one mole of hydrogen in presence of Ni forms a compound C. One mole of compound C on combustion forms two moles of CO2 and 3 moles of H2O. Identify the compounds A, B and C and write the chemical equations of the reactions involved. 

Solution 57:

Compound A indicates Ethanol.

Formula for Ethanol is CH3CH2OH.

CH3CH2OH (in the presence of concentrated H2SO4) → CH2-CH2+ H2O

 

Compound B indicates Ethane.

Formula for compound B is CH2= CH2

CH2=CH2 (in the presence of Ni)  → C2H6

 

Compound C = CH3 — CH3

2C2H6 + 7O2 4CO2 + 6H2O

Chapter 16 Sustainable Management of Natural Resources
NCERT Exemplar Solutions Class 10 Science Management of Natural Resources