Class 10 Science · Chapter 4

Carbon and its Compounds

442 Class 10 Science questions on Carbon and its Compounds from the NCERT textbook, NCERT Exemplar and CBSE board papers 2017–2026, each with its answer and a step-by-step solution.

CBSE Class 10 Science previous year papers, with answers →

Questions · page 11 of 23

1. Q201 CBSE 2024
   1. (i)Define a homologous ​series of carbon compounds.
   2. (ii)Why is ​the melting and ​boiling points ​of ${\text{C}}_4{\text{H}}_8$ higher than that of ${\text{C}}_3{\text{H}}_6$ or ${\text{C}}_2{\text{H}}_4$ ?
   3. (iii)Why do we ​NOT see ​any gradation in chemical properties of a homologous series compounds ?
   4. (iv)Write the name and structures of (i) ​aldehyde and (ii) ketone with molecular form ${\text{C}}_3{\text{H}}_6\text{O}$.
   Show answer

   Chemical properties are similar because the functional group is the same; heavier ${\text{C}}_4{\text{H}}_8$ melts and boils higher; propanal and propanone fit ${\text{C}}_3{\text{H}}_6\text{O}$.

   (i) A homologous series is a series of carbon compounds in which the same functional group substitutes for hydrogen in a carbon chain; successive members differ by a $-{\text{CH}}_2-$ unit ($14$ u), share one general formula and have similar chemical properties. (ii) ${\text{C}}_2{\text{H}}_4$, ${\text{C}}_3{\text{H}}_6$ and ${\text{C}}_4{\text{H}}_8$ are successive members of the alkene series, with molecular masses $28$ u, $42$ u and $56$ u. Melting and boiling points increase with molecular mass in a homologous series, so ${\text{C}}_4{\text{H}}_8$, the largest and heaviest molecule, has the highest melting and boiling points. (iii) Chemical properties are determined by the functional group, and every member of a homologous series has the same functional group, so the members show similar chemical properties with no gradation. (iv) Aldehyde: propanal, ${\text{CH}}_3-{\text{CH}}_2-\text{CHO}$; ketone: propanone, ${\text{CH}}_3-\text{CO}-{\text{CH}}_3$. Both have the formula ${\text{C}}_3{\text{H}}_6\text{O}$ (full structures in the figure).

   Step-by-step solution →
2. Q202 CBSE 2024
   1. (i)​Define the ​term functional group. Identify the functional groups present in the following ​carbon compounds :
   2. (ii)What ​happens when ethanol reacts with acidified potassium dichromate solution ​? Write chemical equation for the reaction. Why is this reaction considered an oxidation reaction ?
   3. (iii)Write chemical equation for the ​reaction ​of ethanoic acid with sodium hydroxide.

   Show answer

   A functional group gives a compound its characteristic properties; (I) has a ketone group, (II) a carboxylic acid group; ethanol is oxidised to ethanoic acid.

   (i) A functional group is an atom or group of atoms that gives a carbon compound its characteristic properties, regardless of the length of its carbon chain. (I) contains the ketone group, $>\text{C}=\text{O}$ (propanone); (II) contains the carboxylic acid group, $-\text{COOH}$ (propanoic acid). (ii) Ethanol is oxidised to ethanoic acid, and the orange dichromate solution turns green: ${\text{CH}}_3{\text{CH}}_2\text{OH}\underset{\text{heat}}{\overset{{\text{acidified K}}_2{\text{Cr}}_2{\text{O}}_7}{\to }}{\text{CH}}_3\text{COOH}$. It is an oxidation because oxygen is added to ethanol (and hydrogen is removed from it). (iii) ${\text{CH}}_3\text{COOH}+\text{NaOH}\to {\text{CH}}_3\text{COONa}+{\text{H}}_2\text{O}$.

   Step-by-step solution →
3. Q203 CBSE 2024
   1. (i)Give reason why carbon can neither form ${\text{C}}^{4+}$ cations nor ${\text{C}}^{4-}$ anions but form covalent compounds.
   2. (ii)What is homologous series of ​carbon ​compound ? Write the molecular formula of any two ​consecutive members of ​homologous series of aldehydes.
   3. (iii)Draw the structure ​of ​the molecule of cyclohexane (${\text{C}}_6{\text{H}}_{12}$).
   Show answer

   Carbon shares its four valence electrons; ${\text{CH}}_2\text{O}$ and ${\text{C}}_2{\text{H}}_4\text{O}$ are consecutive aldehydes; cyclohexane is a ring of six carbon atoms with single bonds.

   (i) Carbon (atomic number 6, configuration 2, 4) has four valence electrons. To form ${\text{C}}^{4-}$ it would have to gain four electrons, and it would be difficult for a nucleus with six protons to hold ten electrons; to form ${\text{C}}^{4+}$ it would have to lose four electrons, which needs a large amount of energy and would leave six protons holding only two electrons. Carbon therefore shares its four valence electrons with other atoms and forms covalent bonds, so its compounds are covalent. (ii) A homologous series is a series of carbon compounds with the same functional group and the same general formula, in which successive members differ by a $-{\text{CH}}_2-$ unit (14 u); the members have similar chemical properties and show a gradation in physical properties. Two consecutive aldehydes: methanal, $\text{HCHO}$ (molecular formula ${\text{CH}}_2\text{O}$), and ethanal, ${\text{CH}}_3\text{CHO}$ (molecular formula ${\text{C}}_2{\text{H}}_4\text{O}$). (iii) Cyclohexane, ${\text{C}}_6{\text{H}}_{12}$: six carbon atoms joined in a ring by single bonds, each carbon also bonded to two hydrogen atoms, as drawn in the structure.

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4. Q204 CBSE 2024
   (i) Write the name and formula of

   1. (1)an alcohol and ​
   2. (2)a carboxylic acid having two carbon atoms. (ii) If ​alcohol is X ​and carboxylic acid is Y, ​then (1) what happens ​when X and Y react in the presence of an acid catalyst ? Write chemical equation for the reaction. (2) what happens when X is heated in ​excess of conc. sulphuric acid at 443 K ? Write the role of conc. ​sulphuric acid in the ​reaction.
   Show answer

   Ethanol and ethanoic acid form ethyl ethanoate by esterification; ethanol gives ethene with hot conc. sulphuric acid acting as a dehydrating agent.

   (i) (1) Ethanol, ${\text{C}}_2{\text{H}}_5\text{OH}$ (${\text{CH}}_3{\text{CH}}_2\text{OH}$); (2) Ethanoic acid (acetic acid), ${\text{CH}}_3\text{COOH}$. (ii) (1) X and Y react to form a sweet-smelling ester, ethyl ethanoate, and water; this is esterification: ${\text{CH}}_3\text{COOH}+{\text{CH}}_3{\text{CH}}_2\text{OH}\stackrel{\text{acid}}{\to }{\text{CH}}_3{\text{COOCH}}_2{\text{CH}}_3+{\text{H}}_2\text{O}$. (2) Ethanol loses a molecule of water and ethene is formed: ${\text{CH}}_3{\text{CH}}_2\text{OH}\underset{443\text{K}}{\overset{{\text{hot conc. H}}_2{\text{SO}}_4}{\to }}{\text{CH}}_2={\text{CH}}_2+{\text{H}}_2\text{O}$. Concentrated sulphuric acid acts as a dehydrating agent: it removes water from ethanol.

   Step-by-step solution →
5. Q205 CBSE 2024
   1. (i)​Write the name and structure of ​an organic compound ‘X’ having two carbon ​atoms in its ​molecule and its ​name is suffixed with ‘–ol’.
   2. (ii)What happens when ‘X’ is heated ​with excess concentrated sulphuric acid at 443 K? ​Write chemical equation for the reaction stating the conditions for the reaction. Also state the role ​played by concentrated sulphuric acid in the reaction.
   3. (iii)Name and draw the electron dot structure of hydrocarbon produced in the above reaction.
   Show answer

   X is ethanol; hot concentrated sulphuric acid dehydrates it at 443 K to ethene, whose carbon atoms share a double bond.

   (i) 'X' is ethanol, ${\text{C}}_2{\text{H}}_5\text{OH}$; its structure is ${\text{CH}}_3-{\text{CH}}_2-\text{OH}$ (the first carbon carries three H atoms, the second carbon two H atoms and the $-\text{OH}$ group). (ii) Ethanol is dehydrated to ethene: ${\text{CH}}_3-{\text{CH}}_2\text{OH}\underset{443\text{K}}{\overset{{\text{hot conc. H}}_2{\text{SO}}_4}{\to }}{\text{CH}}_2={\text{CH}}_2+{\text{H}}_2\text{O}$. Conditions: heating at $443$ K with excess concentrated sulphuric acid. Concentrated sulphuric acid acts as a dehydrating agent: it removes water from ethanol. (iii) The hydrocarbon is ethene, ${\text{C}}_2{\text{H}}_4$ (${\text{CH}}_2={\text{CH}}_2$). In its electron dot structure the two carbon atoms share two pairs of electrons (a double bond) and each carbon shares one pair with each of its two hydrogen atoms, so every carbon has an octet (see the figure).

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6. Q206 CBSE 2024
   1. (i)Describe ​method ​of ​preparation ​of soap giving chemical ​equation for the reaction involved.
   2. (ii)Explain with ​diagram the mechanism of the cleansing action of soaps.
   Show answer

   Soap is made by heating fat with sodium hydroxide (saponification); its molecules form micelles around oily dirt, which is washed away.

   (i) Soap is prepared by saponification: a vegetable oil or animal fat (an ester of fatty acids with glycerol) is heated with sodium hydroxide solution, with stirring; common salt is then added so that the soap separates out, leaving glycerol in the solution. Equation: $({\text{C}}_{17}{\text{H}}_{35}\text{COO}{)}_3{\text{C}}_3{\text{H}}_5+3\text{NaOH}\to 3{\text{C}}_{17}{\text{H}}_{35}\text{COONa}+{\text{C}}_3{\text{H}}_5(\text{OH}{)}_3$ (fat + sodium hydroxide → soap + glycerol). (ii) A soap molecule has a long hydrocarbon tail that dissolves in oil and an ionic end, $-{\text{COO}}^{-}{\text{Na}}^{+}$, that dissolves in water. Around oily dirt the molecules form a micelle: the tails point into the oil at the centre and the ionic ends face the water. The micelles stay suspended in the water because their charged surfaces repel one another, so the dirt trapped inside them is washed away on rinsing, as the micelle diagram shows.

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7. Q207 CBSE 2024
   (i) ​Name ​a ​commercially important carbon compound having functional group $-\text{OH}$ and write ​its molecular formula. (ii) Write chemical equation to show its reaction with

   1. (1)Sodium metal
   2. (2)Excess conc. sulphuric acid
   3. (3)Ethanoic acid in the presence of an acid catalyst
   4. (4)Acidified potassium dichromate Also write the name of the product formed in each case.
   Show answer

   Ethanol (${\text{C}}_2{\text{H}}_6\text{O}$) gives sodium ethoxide, ethene, ethyl ethanoate and ethanoic acid with sodium, conc. sulphuric acid, ethanoic acid and dichromate.

   (i) Ethanol (ethyl alcohol); molecular formula ${\text{C}}_2{\text{H}}_5\text{OH}$ (that is, ${\text{C}}_2{\text{H}}_6\text{O}$). (ii) (1) $2\text{Na}+2{\text{CH}}_3{\text{CH}}_2\text{OH}\to 2{\text{CH}}_3{\text{CH}}_2{\text{O}}^{-}{\text{Na}}^{+}+{\text{H}}_2$; product: sodium ethoxide (and hydrogen gas). (2) ${\text{CH}}_3{\text{CH}}_2\text{OH}\stackrel{{\text{hot conc. H}}_2{\text{SO}}_4,443\text{K}}{\to }{\text{CH}}_2={\text{CH}}_2+{\text{H}}_2\text{O}$; product: ethene. (3) ${\text{CH}}_3\text{COOH}+{\text{CH}}_3{\text{CH}}_2\text{OH}\stackrel{\text{acid}}{\to }{\text{CH}}_3{\text{COOCH}}_2{\text{CH}}_3+{\text{H}}_2\text{O}$; product: ethyl ethanoate (an ester). (4) ${\text{CH}}_3{\text{CH}}_2\text{OH}+2[\text{O}]\stackrel{{\text{acidified K}}_2{\text{Cr}}_2{\text{O}}_7,\text{heat}}{\to }{\text{CH}}_3\text{COOH}+{\text{H}}_2\text{O}$; product: ethanoic acid.

   Step-by-step solution →
8. Q208 CBSE 2024
   1. (i)What are structural isomers ? Write the structures of two isomers of butane.
   2. (ii)​Write the name ​and formula of the simplest saturated hydrocarbon. Write the general formula of the homologous series of ​carbon compounds in which this compound can be placed. Using this formula, ​find ​the $2^{\text{nd}}$ member ​of this series. Write chemical equation for the ​reaction when this ​simplest hydrocarbon burns in air.
   Show answer

   Butane has two isomers, n-butane and isobutane; the simplest alkane is methane, the next is ethane, and methane burns to carbon dioxide and water.

   (i) Compounds with the same molecular formula but different structures are called structural isomers. The two isomers of butane, ${\text{C}}_4{\text{H}}_{10}$, are n-butane, ${\text{CH}}_3-{\text{CH}}_2-{\text{CH}}_2-{\text{CH}}_3$ (straight chain), and isobutane (2-methylpropane), ${\text{CH}}_3-\text{CH}({\text{CH}}_3)-{\text{CH}}_3$ (branched chain). (ii) The simplest saturated hydrocarbon is methane, ${\text{CH}}_4$. It belongs to the alkanes, general formula ${\text{C}}_n{\text{H}}_{2n+2}$; with $n=2$ the second member is ethane, ${\text{C}}_2{\text{H}}_6$. Burning in air: ${\text{CH}}_4+2{\text{O}}_2\to {\text{CO}}_2+2{\text{H}}_2\text{O}+\text{heat and light}$.

   Step-by-step solution →
9. Q209 CBSE 2024
   More than three million carbon compounds have been discovered in ​the field of chemistry. ​The diversity of these ​compounds ​is due to the capacity of carbon atoms for bonding with one another as well as ​with other atoms. Most of ​the ​carbon compounds are poor conductors of electricity ​and have low melting and boiling points.

   1. (a)Write the molecular formula of first two members of homologous series having functional group $-\text{Br}$.[1]
   2. (b)Given below are the formulae of some functional groups : Write the name of these functional groups.[1]
   3. (c)(i)What would be observed on adding a 5% alkaline potassium permanganate drop by drop to some warm ethanol taken in a test tube ? State the role of ${\text{KMnO}}_4$ in the reaction and write the chemical equation for the reaction involved.[2]
   4. (c)(ii)OR : Write the name of the compound formed when ethanol is heated at 443 K temperature with excess of conc. ${\text{H}}_2{\text{SO}}_4$. What is the role of conc. ${\text{H}}_2{\text{SO}}_4$ in the reaction ? Write the chemical equation for the reaction involved.[2]
   Show answer

   The first two bromo compounds are ${\text{CH}}_3\text{Br}$ and ${\text{C}}_2{\text{H}}_5\text{Br}$; alkaline permanganate oxidises ethanol to ethanoic acid; hot conc. sulphuric acid gives ethene.

   (a) ${\text{CH}}_3\text{Br}$ (bromomethane) and ${\text{C}}_2{\text{H}}_5\text{Br}$ (bromoethane). (b) (i) Aldehyde group, $-\text{CHO}$; (ii) Ketone group, $>\text{C}=\text{O}$. (c)(i) The purple colour of alkaline potassium permanganate disappears as the first drops are added to the warm ethanol; when it is added in excess, the purple colour persists. Alkaline ${\text{KMnO}}_4$ acts as an oxidising agent: it oxidises ethanol to ethanoic acid. ${\text{CH}}_3{\text{CH}}_2\text{OH}\stackrel{{\text{alkaline KMnO}}_4+\text{heat}}{\to }{\text{CH}}_3\text{COOH}$ (c)(ii) [OR] The compound formed is ethene, ${\text{CH}}_2={\text{CH}}_2$. Concentrated sulphuric acid acts as a dehydrating agent, removing water from ethanol. ${\text{CH}}_3{\text{CH}}_2\text{OH}\underset{443\text{K}}{\overset{{\text{hot conc. H}}_2{\text{SO}}_4}{\to }}{\text{CH}}_2={\text{CH}}_2+{\text{H}}_2\text{O}$

   Step-by-step solution →
10. Q210 CBSE 2024
    Carbon is a versatile element that ​forms the basis of all living organisms and ​many of the things we use. ​A large variety ​of compounds is formed because of ​its tetravalency. Compounds of carbon are formed with oxygen, hydrogen, nitrogen, sulphur, ​chlorine and many other elements. Answer the ​following questions :

    1. (a)What are hydrocarbons ?[1]
    2. (b)List two properties by virtue of which carbon can form a large number of compounds.[1]
    3. (c)(i)Write the formula of the functional group present in (1) aldehydes, and (2) ketones. Write chemical equation for the reaction that occurs between ethanoic acid and ethanol in the presence of a catalyst.[2]
    4. (c)(ii)OR : What are structural isomers ? Write the structures of two isomers of butane (${\text{C}}_4{\text{H}}_{10}$).[2]
    Show answer

    Hydrocarbons contain only carbon and hydrogen; carbon shows catenation and tetravalency; aldehydes have $-\text{CHO}$ and ketones have $>\text{C}=\text{O}$.

    (a) Hydrocarbons are compounds of carbon and hydrogen only, for example methane, ${\text{CH}}_4$. (b) Catenation (carbon atoms join with one another into long chains, branched chains and rings) and tetravalency (each carbon atom forms four bonds with carbon or other atoms). (c)(i) (1) Aldehydes: $-\text{CHO}$; (2) Ketones: $>\text{C}=\text{O}$. Equation: ${\text{CH}}_3\text{COOH}+{\text{CH}}_3{\text{CH}}_2\text{OH}\stackrel{\text{Acid}}{\to }{\text{CH}}_3{\text{COOCH}}_2{\text{CH}}_3+{\text{H}}_2\text{O}$ (ethyl ethanoate, an ester). (c)(ii) Structural isomers are compounds with the same molecular formula but different structures. The two isomers of butane are n-butane, ${\text{CH}}_3-{\text{CH}}_2-{\text{CH}}_2-{\text{CH}}_3$, and isobutane, ${\text{CH}}_3-\text{CH}({\text{CH}}_3)-{\text{CH}}_3$.

    Step-by-step solution →
11. Q211 CBSE 2024
    Ethanol (commonly known ​as alcohol) is an important carbon compound widely used in ​industries, hospitals, etc. Because it is a very good solvent, it is ​used in medicines such ​as cough ​syrups, tincture iodine and many ​tonics. As it is a cleaner fuel, ethanol is used as an additive in petrol in most of ​the developed countries of the world.

    1. (a)Write the structure of ethanol.[1]
    2. (b)Name the products formed when ethanol burns in sufficient air (oxygen).[1]
    3. (c)(i)State what happens when 5% solution of alkaline potassium permanganate is added to warm ethanol. Draw the structure of the product formed and state the role of 5% solution of alkaline potassium permanganate in the reaction.[2]
    4. (c)(ii)OR : State what happens when ethanol is heated with excess conc. ${\text{H}}_2{\text{SO}}_4$ at $443$ K. Draw the structure of the product formed and state the role of conc. ${\text{H}}_2{\text{SO}}_4$ in the reaction.[2]
    Show answer

    Ethanol, ${\text{CH}}_3-{\text{CH}}_2-\text{OH}$, burns to carbon dioxide and water; permanganate oxidises it to ethanoic acid; conc. sulphuric acid dehydrates it to ethene.

    (a) Ethanol is ${\text{CH}}_3-{\text{CH}}_2-\text{OH}$: the first carbon carries three hydrogen atoms, and the second carries two hydrogen atoms and the –OH group, all joined by single bonds (full structure in the figure). (b) Carbon dioxide and water are formed, with heat and light: ${\text{C}}_2{\text{H}}_5\text{OH}+3{\text{O}}_2\to 2{\text{CO}}_2+3{\text{H}}_2\text{O}$. (c)(i) The purple colour of the permanganate disappears at first as ethanol is oxidised to ethanoic acid, ${\text{CH}}_3\text{COOH}$, in which a ${\text{CH}}_3$ group is joined to a carbon carrying a double-bonded oxygen and an –OH group. The alkaline potassium permanganate acts as an oxidising agent: it adds oxygen to ethanol. (c)(ii) Ethanol is dehydrated to ethene, ${\text{CH}}_2={\text{CH}}_2$ (two carbon atoms joined by a double bond, each carrying two hydrogen atoms), and water is removed. The concentrated sulphuric acid acts as a dehydrating agent: it removes water from ethanol.

    Step-by-step solution →
12. Q212 CBSE 2023
    Consider the ​following substances ​:

    1. (i)Acidified ${\text{K}}_2{\text{Cr}}_2{\text{O}}_7$
    2. (ii)Alkaline ${\text{KMnO}}_4$
    3. (iii)​Oxygen
    4. (iv)Hydrogen Out of these, the ​commonly used ​oxidising agents ​are :

    1. (a)(i) and (ii) only
    2. (b)(ii) and (iii) only
    3. (c)(i), (ii) and (iii)
    4. (d)(i), (ii) and (iv)
    Show answer

    (c) (i), (ii) and (iii)

    Step-by-step solution →
13. Q213 CBSE 2023
    Triple ​covalent bond is ​found ​in ​:

    1. (a)${\text{C}}_6{\text{H}}_6$
    2. (b)${\text{C}}_2{\text{H}}_4$
    3. (c)${\text{C}}_3{\text{H}}_4$
    4. (d)${\text{CH}}_3\text{CHO}$
    Show answer

    (c) ${\text{C}}_3{\text{H}}_4$

    Step-by-step solution →
14. Q214 CBSE 2023
    You ​want to test for ​hardness of water but ​hard water is ​not available in the laboratory. Which of the following compounds may be ​dissolved in ​pure water ​to make it hard ?

    1. (i)Hydrogen Carbonate of Sodium
    2. (ii)Sulphate of Magnesium
    3. (iii)Chloride of Calcium
    4. (iv)Carbonate ​of Sodium

    1. (a)(i) and (ii)
    2. (b)(ii) and (iii)
    3. (c)(iii) and (iv)
    4. (d)(i) and (iv)
    Show answer

    (b) (ii) and (iii)

    Step-by-step solution →
15. Q215 CBSE 2023
    When ethanol reacts ​with sodium ​two ​products ​are formed. These ​products are :

    1. (a)Sodium ethanoate and oxygen
    2. (b)Sodium ethanoate and hydrogen
    3. (c)Sodium ethoxide and oxygen
    4. (d)Sodium ethoxide and hydrogen
    Show answer

    (d) Sodium ethoxide and hydrogen

    Step-by-step solution →
16. Q216 CBSE 2023
    Consider the structures of ​the three ​cyclic carbon ​compounds ​A, ​B ​and C given below and select the ​correct option from the following :

    1. (a)A and C are isomers of hexane and B is benzene.
    2. (b)A is an isomer of hexane, B is benzene and C is an isomer of hexene.
    3. (c)A is a saturated cyclic hydrocarbon and B and C are unsaturated cyclic hydrocarbons.
    4. (d)A is cyclohexane and B and C are the isomers of benzene.
    Show answer

    (c) A is a saturated cyclic hydrocarbon and B and C are unsaturated cyclic hydrocarbons.

    Step-by-step solution →
17. Q217 CBSE 2023
    The total ​number of electrons ​shared in the ​formation ​of an ethyne molecule ​is ​:

    1. (a)$6$
    2. (b)$3$
    3. (c)$10$
    4. (d)$4$
    Show answer

    (c) $10$

    Step-by-step solution →
18. Q218 CBSE 2023
    The electron ​dot structure of ​chlorine molecule ​is ​:

    1. (a)Two overlapping circles, each with the symbol Cl; six crosses are drawn round the left atom and six round the right atom, and the overlap holds two crosses and two dots — that is, two shared pairs.
    2. (b)Two overlapping circles, each with the symbol Cl; five crosses round the left atom and five dots round the right atom, and the overlap holds three crosses and three dots — that is, three shared pairs.
    3. (c)Two overlapping circles, each with the symbol Cl; six crosses round the left atom and six dots round the right atom, and the overlap holds one cross and one dot — that is, one shared pair.
    4. (d)Two overlapping circles, each with the symbol Cl; four crosses round the left atom and four dots round the right atom, and the overlap holds two crosses and two dots — that is, two shared pairs.
    Show answer

    (c) Two overlapping circles, each with the symbol Cl; six crosses round the left atom and six dots round the right atom, and the overlap holds one cross and one dot — that is, one shared pair.

    Step-by-step solution →
19. Q219 CBSE 2023
    The correct ​representation ​of ​covalent bonding ​in an ​oxygen molecule ​is :

    1. (a)Diagram (a): four crosses and four dots outside the overlap; two crosses and two dots inside it.
    2. (b)Diagram (b): six crosses and six dots outside the overlap; one cross and one dot inside it.
    3. (c)Diagram (c): five crosses and five dots outside the overlap; one cross and one dot inside it.
    4. (d)Diagram (d): two crosses and two dots outside the overlap; three crosses and three dots inside it.
    Show answer

    (a) Diagram (a): four crosses and four dots outside the overlap; two crosses and two dots inside it.

    Step-by-step solution →
20. Q220 CBSE 2023
    The hydrocarbon which ​will decolourize bromine ​water is ​:

    1. (a)${\text{C}}_2{\text{H}}_6$
    2. (b)${\text{C}}_3{\text{H}}_8$
    3. (c)${\text{C}}_7{\text{H}}_{14}$
    4. (d)${\text{C}}_8{\text{H}}_{18}$
    Show answer

    (c) ${\text{C}}_7{\text{H}}_{14}$

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