Very Short Answer Questions with answers (1-mark each) from the Class 10 CBSE Science Chapter "Carbon and its Compounds" — based on the questions you've listed:
1. Name the element whose one of the allotropic forms is buckminsterfullerene.
Answer: Carbon.
2. What are the two properties of carbon which lead to the formation of a large number of carbon compounds?
Answer: Catenation and tetravalency.
**3. State whether the following statement is true or false:
“Diamond and graphite are the covalent compounds of carbon element (C).”**
Answer: True.
4. Name the scientist who disproved the 'vital force theory' for the formation of organic compounds.
Answer: Friedrich Wöhler.
5. Name the element whose allotropic form is graphite.
Answer: Carbon.
6. In addition to some propane and ethane, LPG cylinders contain mainly two isomers of another alkane. Name the two isomers and write their condensed structural formulae.
Answer:
- n-butane → CH₃–CH₂–CH₂–CH₃
- isobutane → (CH₃)₂CH–CH₃
7. Buckminsterfullerene is a spherical molecule of 60 carbon atoms.
(a) How many hexagons of carbon atoms are present?
Answer: 20
(b) How many pentagons of carbon atoms are present?
Answer: 12
8. Name the black substance of pencil. Will current flow through it?
Answer:
- Substance: Graphite
- Yes, current will flow because graphite conducts electricity.
9. How does graphite act as a lubricant?
Answer:
Graphite has layers of carbon atoms that slide over each other easily due to weak forces between the layers.
10. Name the hardest natural substance known.
Answer: Diamond.
11. Which of the following molecule is called buckminsterfullerene?
- C₉₀
- C₆₀ ✅
- C₇₀
- C₁₂₀
Answer: C₆₀
12. Give the name and structural formula of an alkyl group.
Answer:
- Name: Methyl group
- Structural Formula: –CH₃
13. Write the electron-dot structures for:
(i) Ethane (C₂H₆)
(ii) Ethene (C₂H₄)
(iii) Ethyne (C₂H₂)
Answer:
(Diagrams are best shown visually, but structure description is below)
- (i) Ethane: H–C–C–H with each C having 4 single bonds
- (ii) Ethene: H₂C=CH₂ (double bond between carbons)
- (iii) Ethyne: HC≡CH (triple bond between carbons)
14. Give the IUPAC name of the compound C₂H₆.
Answer: Ethane.
15. Write the structural formula of propene.
Answer: CH₂=CH–CH₃
16. Write the structural formula of propyne.
Answer: CH≡C–CH₃
17. Write the structural formula of butane.
Answer: CH₃–CH₂–CH₂–CH₃
18. What do you call the compounds having the same molecular formula but different structural arrangements?
Answer: Isomers.
19. Write the names of any two isomers of C₅H₁₂.
Answer:
- n-pentane
- isopentane
20. Write down the structural and electron-dot formula of any one isomer of C₆H₁₄ other than n-hexane.
Answer:
- Isomer: 2-methylpentane
- Structural formula: CH₃–CH(CH₃)–CH₂–CH₂–CH₃
- (Electron-dot structure best shown as diagram)
21. Fill in the blanks:
(a) The form of carbon known as black lead is → Graphite
(b) The form of carbon used as a lubricant at high temperature is → Graphite
(c) Compounds of carbon with hydrogen alone are called → Hydrocarbons
(d) CₙH₂ₙ is the general formula of → Alkenes
(e) Hydrocarbons having the formula CₙH₂ₙ₋₂ are called → Alkynes
(f) Ethene and ethyne are examples of → Unsaturated hydrocarbons
(g) Ethyne has → Two carbon-hydrogen single bonds
(h) Carbon compounds have usually → Low melting and boiling points because they are covalent in nature
(i) The property of carbon atoms to form long chains is called → Catenation
(j) The general formula CₙH₂ₙ for cycloalkanes is the same as that of → Alkenes
(k) The IUPAC name of ethylene is → Ethene
(l) The IUPAC name of acetylene is → Ethyne
Short Answer Questions (Type II) with detailed answers for Class 10 CBSE Science – Chapter: Carbon and its Compounds, covering Q12 to Q35:
Q22.
(a) What is the atomic number of carbon? Write its electronic configuration.
(b) What type of chemical bonds are formed by carbon? Why?
(c) Name the three allotropic forms of carbon.
Answer:
(a) Atomic number of carbon = 6
Electronic configuration = 2, 4
(b) Carbon forms covalent bonds because it has four electrons in its outermost shell and needs four more to complete its octet. It neither gains nor loses electrons due to high energy required, so it shares electrons.
(c) The three allotropic forms of carbon are:
- Diamond
- Graphite
- Fullerenes (e.g., Buckminsterfullerene)
Q23.
(a) What is the general name of all the compounds made up of carbon and hydrogen?
(b) Why does carbon form compounds mainly by covalent bonding?
Answer:
(a) The general name is hydrocarbons.
(b) Carbon forms covalent bonds because it has 4 valence electrons and can achieve a stable octet only by sharing electrons with other atoms.
Q24.
(a) What is meant by catenation? Name two elements which exhibit the property of catenation.
(b) Write the names and structural formulae of all the possible isomers of hexane. What is buckminsterfullerene? How is it related to diamond and graphite?
Answer:
(a) Catenation is the property of an element to form bonds with other atoms of the same element, forming chains or rings.
Elements: Carbon and Silicon
(b) Isomers of hexane (C₆H₁₄):
- n-Hexane
- 2-Methylpentane
- 3-Methylpentane
- 3,3-Dimethylbutane
- 2,3-Dimethylbutane
Buckminsterfullerene (C₆₀) is a spherical molecule of carbon atoms arranged like a football. It is an allotrope of carbon like diamond and graphite, but has a closed cage structure.
Q25.
(a) Why is diamond used for making cutting tools (like glass cutters) but graphite is not?
(b) Why is graphite used for making dry cell electrodes but diamond is not?
Answer:
(a) Diamond is extremely hard due to its strong 3D network of covalent bonds. Graphite is soft and slippery due to weak forces between layers.
(b) Graphite conducts electricity because it has free electrons; diamond does not conduct electricity as it has no free electrons.
Q26.
(a) Give the general formula of:
(i) Alkane
(ii) Alkene
(iii) Alkyne
(b) Classify the following compounds:
Answer:
(a)
- Alkane: CₙH₂ₙ₊₂
- Alkene: CₙH₂ₙ
- Alkyne: CₙH₂ₙ₋₂
(b) Classification:
- C₂H₄ – Alkene
- C₃H₄ – Alkyne
- C₄H₈ – Alkene
- C₅H₁₂ – Alkane
- C₅H₈ – Alkyne
- C₃H₈ – Alkane
- CH₄ – Alkane
Q27.
(a) Friedrich Wohler converted an inorganic compound into an organic compound.
(i) Name and formula of inorganic compound:
(ii) Name and formula of organic compound formed:
(b) Give the molecular formula of butane and name its two isomers. Name one fuel containing both.
Answer:
(a)
(i) Inorganic compound: Ammonium cyanate (NH₄OCN)
(ii) Organic compound: Urea (NH₂CONH₂)
(b) Butane – C₄H₁₀
Isomers:
- n-butane
- isobutane
Fuel: LPG (Liquefied Petroleum Gas)
Q28.
(a) Give IUPAC names and formulae of:
- An organic compound with single bonds: Butane (C₄H₁₀)
- With triple bond: Butyne (C₄H₆)
(b) Molecular formula of benzene: C₆H₆
(c) Branched chain: Isobutane
Q29.
Compare the catenation ability of carbon and silicon.
Answer:
Carbon has greater catenation ability than silicon because:
- C–C bonds are stronger than Si–Si bonds
- Carbon forms stable long chains; silicon does not.
Q30.
(a) How can diamonds be made artificially?
(b) Give two differences between diamond and graphite. What causes these differences?
Answer:
(a) Diamonds are made artificially by subjecting graphite to high temperature and pressure.
(b)
- Diamond is hard and an insulator; Graphite is soft and a conductor.
- Caused by difference in structure: Diamond has 3D tetrahedral network; graphite has layered structure.
Q31.
(a) Why does carbon form a large number of compounds?
(b) Write names and structures of isomers of butane.
Answer:
(a) Due to catenation and tetravalency, carbon can form chains and bonds with many elements.
(b)
- n-butane – CH₃–CH₂–CH₂–CH₃
- Isobutane – (CH₃)₂CH–CH₃
Q32.
(a) Give name and structural formula of:
(i) Alkane – Ethane (C₂H₆)
(ii) Alkene – Ethene (C₂H₄)
(iii) Alkyne – Ethyne (C₂H₂)
(iv) Cycloalkane – Cyclohexane (C₆H₁₂)
(b) Common names:
(i) Ethyne – Acetylene
(ii) Ethene – Ethylene
(c) Benzene – Formula: C₆H₆
Structure: A hexagonal ring with alternating double bonds.
Q33.
(a) What is the unique property of carbon atom?
(b) Why is diamond hard while graphite is soft?
Answer:
(a) Catenation and tetravalency. These allow complex compound formation.
(b) Diamond: Strong 3D network
Graphite: Weak forces between layers → soft and slippery
Q34.
(a) Give structure and bonds of:
(i) Ethyne – HC≡CH → 1 triple bond
(ii) Ethene – H₂C=CH₂ → 1 double bond
(iii) Benzene – C₆H₆ → 3 double bonds (alternating)
(b) Cyclohexane – C₆H₁₂
Structure: Hexagonal ring with all single bonds
Covalent bonds: 18
Q35.
(a) Two structural differences between diamond and graphite:
- Diamond: Tetrahedral structure; Graphite: Planar layers
- Diamond: No free electrons; Graphite: Free electrons
(b) Graphite layers slide → lubricant
Diamond is rigid → not suitable
(c) Diamond's hardness makes it ideal for drilling
Graphite is soft, can't drill
(d)
- Diamond is used in jewellery due to brilliance
- Graphite is used in pencils for writing
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