What is covalent bonding in carbon compounds?

Covalent bonding involves sharing of electrons between carbon atoms and other atoms to complete octets.

What are hydrocarbons?

Hydrocarbons are organic compounds consisting of carbon and hydrogen only, classified as alkanes, alkenes, and alkynes.

Are these notes useful for competitive exams?

Yes, these notes help students prepare for NEET, SSC, Railway, Police Bharti exams as well as Class 10 board exams.

1. Why is carbon considered a versatile element?

Because oftetravalency(forms four covalent bonds) andcatenation(ability to form long chains/rings with itself). This produces a huge variety of compounds with different sizes and functional groups.

2. Define a covalent bond. How is it different from ionic bond?

Acovalent bondforms by sharing electron pairs between atoms (usually non-metals). In contrast,ionic bondsform by complete transfer of electrons from a metal to a non-metal, producing ions.

14. How will you test for unsaturation in an organic compound?

Usebromine water(orange to colourless) oracidified KMnO₄(purple to colourless). Alkenes/alkynes decolourise; alkanes do not.

22. Why do covalent compounds generally have low melting/boiling points and poor conductivity?

They consist of neutral molecules with weak intermolecular forces and no free ions/electrons for conduction (exceptions: graphite, conjugated systems).

26. What happens when sodium is added to ethanol?

Effervescence due to H₂ gas; sodium ethoxide is formed: 2C₂H₅OH + 2Na → 2C₂H₅ONa + H₂↑.

27. Reaction of ethanoic acid with carbonates/bicarbonates?

Vigorous effervescence due to CO₂: CH₃COOH + NaHCO₃ → CH₃COONa + H₂O + CO₂↑ (turns limewater milky).

30. Why do many carbon compounds burn with a sooty flame?

Due to incomplete combustion and a higher C:H ratio producing unburnt carbon particles (soot), especially in unsaturated/aromatic compounds.

32. How is ethanol converted to ethene (dehydration)?

By heating ethanol with conc. H₂SO₄ or over Al₂O₃ (catalyst) to eliminate water: C₂H₅OH → C₂H₄ + H₂O.

33. What happens when ethene reacts with cold, dilute KMnO₄?

It gets oxidised to ethane-1,2-diol (ethylene glycol); solution decolourises (Baeyer test).

35. Why do detergents work better than soaps in hard water?

Their sulphate/sulphonate heads do not precipitate with Ca²⁺/Mg²⁺ ions; hence no scum formation and better cleaning.

39. Why do alkanes undergo substitution while alkenes undergo addition reactions?

Alkanes are saturated (no multiple bonds), so substitution replaces H atoms. Alkenes have a π-bond that can break and add atoms across C=C (addition).

40. Why are methane and ethane insoluble in water but soluble in organic solvents?

They are non-polar molecules; water is polar. By “like dissolves like”, non-polar compounds dissolve in non-polar organic solvents.

45. Why does pure ethanoic acid freeze near 16.6 °C (glacial acetic acid)?

Strong hydrogen bonding leads to an ordered dimeric structure and higher freezing point than many organics.

49. Why do soaps form scum in hard water but detergents do not?

Soaps react with Ca²⁺/Mg²⁺ to form insoluble salts (scum). Detergents do not form such precipitates.

Class 10 Science — Chapter 4: Carbon & its Compounds

By RAAM SETU | NEET, SSC, Railway & Police Bharti Focused Notes 📘

📘 Introduction

This chapter explains Carbon & its Compounds including covalent bonding, hydrocarbons, functional groups, reactions, and uses. Essential for NEET, SSC, Railway, Police Bharti exams and Class 10 board exams.

🔹 Key Concepts

Covalent Bonding: Sharing of electrons between atoms
Hydrocarbons: Alkanes, Alkenes, Alkynes
Functional Groups: Alcohols, Carboxylic acids, Amines, Halides
Reactions: Combustion, substitution, addition
Uses of Carbon Compounds: Fuels, plastics, medicines, polymers

📊 Chapter Summary Table

Concept	Example / Reaction	Use
Alkane	CH₄, C₂H₆	Fuel & energy
Alkene	C₂H₄, C₃H₆	Plastics & polymers
Functional Group	–OH, –COOH	Chemical properties & reactions

🧮 Practice Questions

Define covalent bonding with example. ➡ Show Answer
Covalent bonding involves sharing of electrons. Example: H₂, CH₄.
Classify hydrocarbons with examples. ➡ Show Answer
Alkanes: CH₄, C₂H₆; Alkenes: C₂H₄; Alkynes: C₂H₂
Write the reaction of ethanol with sodium. ➡ Show Answer
2CH₃CH₂OH + 2Na → 2CH₃CH₂ONa + H₂↑
Name two uses of carbon compounds. ➡ Show Answer
Fuels, plastics, medicines, polymers

Carbon and its Compounds — 50 Q&A

NCERT Class 10 — Chapter 4. Tap to expand answers. Mobile-friendly.

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Covalent Bonding Functional Groups Soaps & Detergents Nomenclature

NCERT Class 10 — Chapter 4: Carbon and its Compounds

📘 Introduction

🔹 Key Concepts

📊 Chapter Summary Table

🧮 Practice Questions

1. Why is carbon considered a versatile element?

2. Define a covalent bond. How is it different from ionic bond?

3. Draw/describe the covalent structure of methane (CH₄).

4. Compare diamond and graphite (allotropes of carbon).

5. What is catenation? Give examples.

6. What is a homologous series? List its characteristics.

7. Classify hydrocarbons into saturated and unsaturated with examples.

8. List common functional groups and their formulae.

9. Outline steps for IUPAC naming with examples.

10. Describe complete and incomplete combustion of hydrocarbons.

11. What is oxidation of alcohols? Give an equation.

12. Explain hydrogenation (addition) of unsaturated hydrocarbons/oils.

13. What is a substitution reaction? Example with methane.

14. How will you test for unsaturation in an organic compound?

15. List physical properties and uses of ethanol.

16. State key properties and uses of ethanoic (acetic) acid.

17. Explain esterification with an equation and simple diagram.

18. What is saponification? Give the word equation.

19. Describe cleansing action of soap with a micelle diagram.

20. Differentiate between soaps and detergents.

21. What is isomerism? Give an example from C₄H₁₀.

22. Why do covalent compounds generally have low melting/boiling points and poor conductivity?

23. Show the structure of ethene (C₂H₄).

24. Show the structure of ethyne (acetylene) C₂H₂.

25. Name these compounds: (a) CH₃–CH₂–CH₃ (b) CH₃–CH₂–COOH (c) CH₃–O–CH₃ (d) CH₃–CH₂–Cl

26. What happens when sodium is added to ethanol?

27. Reaction of ethanoic acid with carbonates/bicarbonates?

28. State general formulae of alkanes, alkenes, and alkynes.

29. Write a balanced equation for complete combustion of ethanol.

30. Why do many carbon compounds burn with a sooty flame?

31. Identify functional groups: (a) CH₃CHO (b) CH₃COCH₃ (c) CH₃CH₂OH (d) CH₃COOH

32. How is ethanol converted to ethene (dehydration)?

33. What happens when ethene reacts with cold, dilute KMnO₄?

34. Define polymerisation with two examples of addition polymers.

35. Why do detergents work better than soaps in hard water?

36. Give reasons: Carbon forms a large number of compounds.

37. Give molecular formulae: (a) propane (b) but-1-ene (c) ethyne (d) pentan-1-ol

38. Write condensed structural formulae: ethanol, propanol, propanoic acid, acetone, ethanal.

39. Why do alkanes undergo substitution while alkenes undergo addition reactions?

40. Why are methane and ethane insoluble in water but soluble in organic solvents?

41. Write word equations for: oxidation of ethanol; esterification; saponification; hydrogenation of ethene.

42. Predict product: C₂H₄ + Br₂ → ? (and observation)

43. Differentiate aldehydes and ketones (functional group & naming).

44. Name the compound CH₃–CH₂–CH₂–OH and CH₃–CH(OH)–CH₃.

45. Why does pure ethanoic acid freeze near 16.6 °C (glacial acetic acid)?

46. Give two everyday uses each of ethanol and acetic acid.

47. Classify as saturated/unsaturated: CH₄, C₃H₆, C₂H₂, C₄H₁₀.

48. State products of (a) dehydration of alcohols (b) hydrogenation of alkenes.

49. Why do soaps form scum in hard water but detergents do not?

50. Why are many organic compounds used as fuels? Give two examples.