Extra Questions for Class 10 Science Chapter 4 Carbon and Its Compounds
Q1. Why does carbon forms large number of compounds?
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Answer:Carbon forms large number of compounds because of tetravalency and catenation property.
Tetravalency – Carbon has valency 4, to attain noble gas configuration carbon share its valence electrons with other elements like hydrogen, chlorine, etc.
Catenation – Carbon also shows the property of self-linking in which it forms long, branched or cyclic chains to form large number of compounds.
Q2. What is the reactive site in the given hydrocarbon? Write its name.
H3C—CH2—CH=CH—CH3
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Answer:The reactive site is at a place where double bond is present.
Name of the compound is 2-pentene.
Q3. Why acetic acid is called glacial acetic acid?
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Answer:Acetic acid has very low melting point i.e. 290 K, hence it freezes during winters in cold countries. So it is called glacial acetic acid.
Q4. Write the structural formula for bromopentane and ethanoic acid.
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Answer:
Q5. What is the difference in the number of carbon and hydrogen atoms between two
successive members of a homologous series? Also give the difference in their atomic masses.
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Answer:The difference is of 1 carbon and two hydrogen atoms i.e., —CH2 and mass difference is 14 a.m.u.
Q6. How does ethanoic acid react with carbonates and hydrogen carbonates? Show it with
the equation.
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Answer:
Q7. Name the peculiar/specific chemical property exclusive in case of saturated hydrocarbons
and unsaturated hydrocarbons.
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Answer:Saturated hydrocarbons show substitution reaction in which hydrogen atom gets substituted by other elements or atoms. Unsaturated hydrocarbons show addition reaction, in which hydrogen atom gets added across the double bond or triple bond of the compound.
Q8. Draw the structures of two isomers of butane.
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Answer:
Q9. Name the functional groups of the following:
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Answer:(b) Carboxylic acid
(c) Ketone
(d) Alcohol
Q10. Explain substitution reaction with example.
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Answer:The reaction of saturated hydrocarbon with chlorine in which each hydrogen atom slowly gets substituted with chlorine atom is called substitution reaction.
Q11. Differentiate between saturated and unsaturated hydrocarbons. Give one example for
each.
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Answer:
Q12. A student burns a hydrocarbon in air and obtains sooty flame. Give two reasons for this
observation.
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Answer:Sooty flame could be obtained due to
(i) Incomplete combustion of saturated hydrocarbons.
(ii) Combustion of unsaturated hydrocarbon.
Q13. Write the general formula for each of the following hydrocarbons and give one example
for each. (i) Alkene (ii) Alkyne
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Answer:
Q14. Diamond and graphite show different physical properties although they are made up of
carbon and shows same chemical properties. What is this property called?
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Answer: This property is allotropy.The physical properties are different because the carbon-carbon bonding in both the cases varies. In diamond one carbon atom is bonded with four other carbon atoms with strong covalent bond so it is hard, while in case of graphite each carbon forms two strong bonds with other two carbon atoms and one weak bond is formed with third carbon atom and forms hexagonal rings which slide over each other, so it is soft.
Q15. Give difference between soap and detergent.
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Answer:
Q16. What is denatured alcohol?
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Answer:When ethanol is mixed with methanol or some poisonous substances such as copper sulphate, pyridine which makes it unfit for drinking such alcohol is called denatured alcohol.
Q17. What is esterification and give its uses?
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Answer:It is the reaction in which esters are formed by reacting carboxylic acid with alcohol in the presence of concentrated sulphuric acid.
Q18. Differentiate between ethanol and ethanoic acid on basis of the following test:
(i) Blue litmus test (ii) Reaction with sodium bicarbonate (iii) Sodium metal test
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Answer:
Q19. How can you obtain the following from pure ethanol:
(i) Ethene (ii) Ethanoic acid (iii) Ester?
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Answer:
Q20. Giving chemical equations of the reactions write what happens when
(i) Ethanol is heated with excess of concentrated sulphuric acid at 443 K.
(ii) Ethanoic acid reacts with ethanol in presence of an acid.
(iii) Ester with molecular formula CH3COOC2H5 reacts with sodium hydroxide.
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Answer: