CBSE Important Questions Class 10 Science Chapter 4 Carbon and Its Compounds

Carbon and its Compounds is the fourth chapter of Class 10 Science. It explains covalent bonding in carbon compounds, the versatile nature of carbon, hydrocarbons and functional groups, and important compounds such as ethanol and ethanoic acid along with their reactions.

CBSE Important Questions Class 10 Science Chapter 4 Carbon and Its Compounds

Carbon and its Compounds
Medium
Q.
Ethane, with the molecular formula C2H6 has

(a) 6 covalent bonds.
(b) 7 covalent bonds.
(c) 8 covalent bonds.
(d) 9 covalent bonds.
Carbon and its Compounds
Medium
Q.
Butanone is a four-carbon compound with the functional group

(a) carboxylic acid.
(b) aldehyde.
(c) ketone.
(d) alcohol.
Carbon and its Compounds
Medium
Q.
While cooking, if the bottom of the vessel is getting blackened on the outside, it means that

(a) the food is not cooked completely.
(b) the fuel is not burning completely.
(c) the fuel is wet.
(d) the fuel is burning completely.
Carbon and its Compounds
Medium
Q.
Explain the nature of the covalent bond using the bond formation in CH3Cl.
Carbon and its Compounds
Difficult
Q.
Draw the electron dot structures for

(a) ethanoic acid.
(b) H2S.
(c) propanone.
(d) F2.
Carbon and its Compounds
Medium
Q.
What is a homologous series? Explain with an example.
Carbon and its Compounds
Medium
Q.
How can ethanol and ethanoic acid be differentiated on the basis of their physical and chemical properties?
Carbon and its Compounds
Medium
Q.
Why does micelle formation take place when soap is added to water? Will a micelle be formed in other solvents such as ethanol also?
Carbon and its Compounds
Medium
Q.
Why are carbon and its compounds used as fuels for most applications?
Carbon and its Compounds
Medium
Q.
Explain the formation of scum when hard water is treated with soap.
Carbon and its Compounds
Easy
Q.
What change will you observe if you test soap with litmus paper (red and blue)?
Carbon and its Compounds
Medium
Q.
What is hydrogenation? What is its industrial application?
Carbon and its Compounds
Easy
Q.
Which of the following hydrocarbons undergo addition reactions:
C2H6, C3H8, C3H6, C2H2 and CH4
Carbon and its Compounds
Medium
Q.
Give a test that can be used to differentiate chemically between butter and cooking oil.
Carbon and its Compounds
Medium
Q.
Explain the mechanism of the cleaning action of soaps.

CBSE Important Questions Class 10 Science Chapter 4 Carbon and Its Compounds

These CBSE important questions cover the properties of covalent compounds and the reaction of ethanoic acid with sodium carbonate, including an assertion-reason question. Every question has a clear answer with the chemical equations students need for the board exam.

CBSE Important Questions Class 10 Science – Carbon and its Compounds

Q1. Covalent compounds are / have generally (1 mark)

  1. poor conductors of electricity
  2. less strong bonds
  3. high intermolecular forces
  4. high melting and boiling points

Answer:

(a) poor conductors of electricity.

Covalent compounds are formed by sharing of electrons. They do not contain ions, so they cannot conduct electricity.

Covalent bonding in methane and properties of covalent compounds
Covalent bonding in methane and properties of covalent compounds

Q2. What happens when ethanoic acid reacts with sodium carbonate? Write the chemical equation of the reaction involved. (5 marks)

Answer:

Ethanoic acid reacts with sodium carbonate to form sodium ethanoate, water and carbon dioxide gas. The carbon dioxide is given off with brisk effervescence and turns lime water milky.

2CH₃COOH + Na₂CO₃ → 2CH₃COONa + H₂O + CO₂↑

Q3. A covalent compound (1 mark)

  1. has definite geometry
  2. has strong bonds
  3. is a poor conductor of electricity and has low melting and boiling points
  4. is an electrolyte

Answer:

(c) is a poor conductor of electricity and has low melting and boiling points.

The forces between the molecules of covalent compounds are weak, so they melt and boil at low temperatures, and having no ions, they do not conduct electricity.

Q4. Covalent compounds (1 mark)

  1. have definite geometry
  2. have high melting and boiling points
  3. are poor conductors of electricity
  4. are electrolytes

Answer:

(c) are poor conductors of electricity.

Covalent compounds have no free ions, so they do not conduct electricity.

Q5. Pick the one which is not a property of covalent compounds. (1 mark)

  1. Low boiling point
  2. Low melting point
  3. Good conductors of electricity
  4. Bad conductors of electricity

Answer:

(c) Good conductors of electricity.

Covalent compounds are bad conductors of electricity because they do not contain ions.

Q6. Assertion (A): Covalent compounds are poor conductors of electricity. Reason (R): Covalent compounds contain ions. (1 mark)

  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and R are true but R is not the correct explanation of A.
  3. A is true but R is false.
  4. Both A and R are false.

Answer:

(c) A is true but R is false.

Covalent compounds are poor conductors of electricity because they do not contain ions. Their atoms are joined by sharing electrons.

Related Study Material on Extramarks

Q.1 Answer the following questions:
a) Which functional group can be present in an organic compound having the molecular formula C2H4O? Write its structure.
b) Give the name of the compounds having the following functional groups:
i) Aldehyde group
ii) Halo group
iii) Alkene group
iv) Alkyne group

Marks:3
Ans

a) Aldehyde group (-CHO) is present in C2H4O. Its structure is:

b)

i) Aldehyde group- Ethanal
CH3 CH2CH2COOH
ii) Halo group- Chloromethane
CH3CHO
iii) Alkene group- Ethene
CH2 CH2
iv) Alkyne group- Ethyne

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FAQs (Frequently Asked Questions)

The two key properties are catenation and tetravalency. Catenation is the ability of carbon to form strong bonds with other carbon atoms, creating chains, branched chains, and rings of different lengths. Tetravalency means carbon has a valency of four, allowing it to bond with four different atoms — hydrogen, oxygen, nitrogen, sulphur, and chlorine. Together, these two properties generate millions of carbon compounds.

Detergents are sulphonic acid salts. Their charged ends do not react with Ca²⁺ and Mg²⁺ ions in hard water to form insoluble precipitates. Soaps react with these ions to form scum, which reduces cleaning efficiency and wastes soap. Detergents produce lather and clean equally well in both hard and soft water.

Alkaline KMnO₄ acts as an oxidising agent. It adds oxygen to carbon compounds, converting an alcohol to a carboxylic acid. The purple colour of KMnO₄ gets discharged as it oxidises the alcohol. Once all the alcohol is consumed, excess KMnO₄ retains its purple colour.

A homologous series is a group of carbon compounds with the same functional group and similar chemical properties. Successive members differ by –CH₂– and 14 u in molecular mass. Knowing one member’s properties lets you predict the behaviour of all others in the series. Physical properties like boiling point show a gradual trend while chemical reactivity remains similar throughout.

The soap cleaning mechanism, esterification, saponification, compound identification (PYQ-style X → Y → Z questions), catenation and tetravalency, and the bromine water test appear most consistently across board papers. These topics together cover the majority of marks from this chapter in 2026 CBSE exams.

Saturated hydrocarbons have only single bonds between carbon atoms and carry the maximum number of hydrogen atoms. They follow the formula CₙH₂ₙ₊₂ and are less reactive. Unsaturated hydrocarbons have at least one double or triple bond between carbon atoms, carry fewer hydrogen atoms, and are more reactive. They undergo addition reactions whereas saturated hydrocarbons undergo substitution reactions.