Many students like you often get lost in the maze of chemical equations, reactions, and the many unrelated concepts in the chapter Carbon and Its Compounds.
On top of that, there’s a high chance of missing important points in such a long chapter. Carbon And Its Compounds MCQs is a small attempt from Studyless to ease that pain a little.
You can follow this simple three-step process to master Chapter 4 — Carbon and Its Compounds:
- Read the chapter from your NCERT book at least 20 to 30 times.
- Learn and memorize the short notes on studyless.in.
- Then practice with the MCQs and quizzes.
The MCQs are presented in two forms:
First we have the actual MCQs with answer and explanantions. Then is the Quiz section.
Click on the Jump To Quiz Section Button to go directly to the Quiz section.
Bonding in Carbon: The Covalent Bond
Q1 Carbon’s valency is 4 because:
A. It can easily lose 1 electron
B. It can gain 7 electrons
C. It has 4 electrons in its outermost shell
D. It has a completely filled shell
Answer: C
Explanation: The atomic number of carbon is 6, so its electronic configuration is 2,4. It has 4 valence electrons and needs 4 more to achieve noble gas configuration.
Q2 Carbon does not form C⁴⁺ or C⁴⁻ ions because:
A. It is radioactive
B. It reacts only with oxygen
C. Gaining or losing 4 electrons is energetically difficult
D. It prefers losing only one electron
Answer: C
Explanation: Gaining 4 electrons makes it hard for a nucleus with 6 protons to hold 10 electrons. Losing 4 requires too much energy. Hence carbon shares electrons instead.
Q3. In the electron dot structure of H₂, the bond formed is a:
A. Double covalent bond
B. Single covalent bond
C. Triple covalent bond
D. Ionic bond
Answer: B
Explanation: Each H atom shares one electron, forming one shared pair = a single covalent bond.
Q4. Which molecule contains a double bond?
A. H₂
B. Cl₂
C. O₂
D. H₂O
Answer: C
Explanation: Each oxygen needs 2 electrons to complete its octet, so O₂ forms a double bond.
Q5. Nitrogen forms a triple bond because each nitrogen atom:
A. Needs 1 electron
B. Needs 2 electrons
C. Needs 3 electrons
D. Already has an octet
Answer: C
Explanation: Nitrogen (atomic number 7) has 5 valence electrons and needs 3 more, so N₂ is formed by sharing 3 pairs of electrons.
Q6. What mistake, if any, has the student made?
A. Oxygen should form a double bond with H
B. Hydrogen should form a triple bond
C. No mistake — water has two single covalent bonds
D. Water has ionic bonds
Answer: C
Explanation: Oxygen has 6 valence electrons and needs 2 more, which it gets by forming two single covalent bonds with two hydrogen atoms.
Q7.Carbon compounds with covalent bonds generally:
A. Have high melting points
B. Conduct electricity
C. Are poor conductors of electricity
D. Form ions in solution
Answer: C
Explanation: Covalent compounds do not form ions, hence they are poor electrical conductors.
Q8.Which carbon compound has the lowest boiling point?
A. Chloroform
B. Ethanol
C. Acetic acid
D. Methane
Answer: D
Explanation: methane has the lowest boiling point (111 K).
Q9. Covalent compounds have low melting and boiling points because:
A. Covalent bonds break easily
B. Intermolecular forces are weak
C. They contain ions
D. They react with metals
Answer: B
Explanation: Covalent molecules have strong intramolecular bonds but weak intermolecular forces, causing low MP and BP.
Q10. Case: A teacher heats methane and observes no electrical conduction.
Which conclusion is correct?
A. Methane contains ions
B. Methane contains free electrons
C. Methane is a covalent compound
D. Methane undergoes dissociation
Answer: C
Explanation: Methane is covalent and does not produce ions; therefore it does not conduct electricity.
Q12. Carbon shares electrons instead of gaining/losing because:
A. Sharing allows it to achieve noble gas configuration
B. It has 8 electrons
C. It is metallic
D. It has 2 valence electrons
Answer: A
Explanation: Sharing 4 electrons allows both carbon and its partner atoms to complete outer shells.
Q13. Which molecule shown in the diagrams forms four single covalent bonds?
A. H₂
B. N₂
C. O₂
D. CH₄
Answer: D
Explanation: methane (CH₄) where carbon forms four single covalent bonds with H atoms.
COVALENT
Allotropes of Carbon
Q1. Which of the following is not an allotrope of carbon discussed in the chapter?
A. Diamond
B. Graphite
C. Fullerene (C-60)
D. Carbon monoxide
Answer: D
Explanation: Page 61 of discusses diamond, graphite, and fullerenes (C-60) as carbon allotropes. Carbon monoxide is a compound, not an allotrope.
Q2. According to the structure diagram on page 61, each carbon atom in diamond is bonded to:
A. 2 other carbon atoms
B. 3 other carbon atoms
C. 4 other carbon atoms
D. 6 other carbon atoms
Answer: C
Explanation: The diagram and text state that in diamond, each carbon atom is bonded to four other carbon atoms in a rigid 3-D structure.
Q3. Graphite conducts electricity because:
A. All its bonds are single bonds
B. Each carbon atom forms 4 bonds
C. It contains free electrons due to one delocalized electron
D. It reacts with air
Answer: C
Explanation: In graphite, each carbon atom forms 3 bonds in hexagonal layers, leaving one free electron, making graphite a good conductor.
Q4. Diamond is the hardest natural substance because:
A. It has layers that slide
B. It contains weak forces
C. It forms a rigid three-dimensional network
D. It has double bonds
Answer: C
Explanation: Diamond’s extreme hardness comes from its rigid 3-D structure where every carbon atom is strongly bonded to four others.
Q5. A student observes that graphite is slippery and smooth.
Which structural feature explains this?
A. Strong bonds in all directions
B. Layers of carbon atoms that slide over each other
C. Spherical carbon arrangement
D. Carbon atoms arranged in a cube
Answer: B
Explanation: Graphite has layers of hexagonal carbon sheets placed one above another that can slide easily.
Q6. Fullerene (C-60) is named after:
A. Rutherford
B. Newlands
C. Buckminster Fuller
D. Kekulé
Answer: C
Explanation: C-60 resembles the geodesic dome designed by Buckminster Fuller, hence the name “Buckminsterfullerene.”
Q7. Why do diamond and graphite show different physical properties despite both being made of carbon?
A. They have different numbers of electrons
B. Their carbon atoms bond in different arrangements
C. One contains hydrogen
D. Graphite is not pure carbon
Answer: B
Explanation: Page 61 your NCERT book states that although chemically the same, their bonding arrangements differ, leading to very different properties.
Q8. A scientist creates artificial diamonds by using very high pressure and temperature.
This process works because:
A. Carbon atoms move randomly
B. Diamond forms under conditions of extremely high pressure
C. Graphite melts easily
D. Carbon has low density
Answer: B
Explanation: Synthetic diamonds are made by subjecting carbon to very high pressure and temperature.
Q9. What shape does the fullerene C-60 resemble?
A. Cube
B. Football
C. Pyramid
D. Cylinder
Answer: B
Explanation: Page 61 of your NCERT book clearly describes and shows C-60 arranged in the shape of a football.
Q10. Which one of these statements is true?
A. Diamond conducts electricity; graphite does not
B. Both diamond and graphite conduct electricity
C. Diamond is soft; graphite is hard
D. Graphite conducts electricity; diamond does not
Answer: D
Explanation: Graphite conducts electricity due to free electrons, while diamond lacks free electrons and does not conduct electricity.
Q11. The structure of graphite contains:
A. Tetrahedral carbon arrangement
B. Carbon atoms bonded to four other atoms
C. Hexagonal layers with one double bond
D. Spherical carbon cages
Answer: C
Explanation: graphite has hexagonal arrays, where one of the bonds is a double bond.
Q12. Which property is common to all allotropes of carbon?
A. Same physical properties
B. Same crystalline structure
C. Same chemical properties
D. Same hardness
Answer: C
Explanation: allotropes have different physical but same chemical properties because they are all pure carbon.
Q13. A jeweler needs a material that does not wear out and is very hard.
Which allotrope best fits the requirement?
A. C-60
B. Graphite
C. Diamond
D. Coal
Answer: C
Explanation: Diamond is the hardest substance known as per the chapter.
Q14. Graphite is used as a lubricant because:
A. It reacts with oils
B. It forms micelles
C. Its layers slide over each other
D. It dissolves in water
Answer: C
Explanation: The smooth and slippery nature of graphite comes from its layered structure.
Q15. Which allotrope is most likely to act as a conductor in electronic devices?
A. Diamond
B. C-60
C. Graphite
D. Charcoal
Answer: C
Explanation: Only graphite conducts electricity effectively among the allotropes mentioned.
Quiz Allotropes
ALLOTROPES
Versatile Nature of Carbon
Q1.
Which property of carbon explains why it can form millions of compounds?
A. Its radioactivity
B. Its large atomic size
C. Tetravalency and catenation
D. Its metallic nature
Answer: C
Explanation: Carbon forms a huge variety of compounds due to tetravalency and catenation.
Q2.
Carbon forms compounds with chains, branches, and rings mainly because:
A. It loses electrons easily
B. It has weak bonds
C. It can bond with carbon repeatedly
D. It forms ions in solution
Answer: C
Explanation: Carbon’s ability to bond repeatedly with itself (catenation) allows long chains, branches, and rings.
Q3.
Carbon–carbon bonds are very stable because:
A. Carbon atoms are very large
B. Carbon atoms are very small
C. Carbon has 8 valence electrons
D. Carbon always forms double bonds
Answer: B
Explanation: Carbon’s small atomic size helps the nucleus hold shared electrons strongly, forming stable bonds.
Q4.
Which of the following is a characteristic of saturated carbon compounds?
A. They contain double or triple bonds
B. They are usually more reactive
C. They contain only single bonds
D. They cannot form chains
Answer: C
Explanation: Saturated compounds contain only C–C single bonds.
Q5.
Unsaturated carbon compounds contain:
A. Only C–H single bonds
B. C–C double or triple bonds
C. Only ionic bonds
D. No carbon atoms
Answer: B
Explanation: Unsaturated compounds have double or triple carbon–carbon bonds.
Q6.
Which element can form chains like carbon but only up to 7–8 atoms and is unstable?
A. Nitrogen
B. Oxygen
C. Silicon
D. Sulphur
Answer: C
Explanation: Silicon forms chains of about 7–8 atoms, but these compounds are very reactive and unstable.
Q7.
Carbon can form stable bonds with hydrogen, oxygen, nitrogen, sulphur, and chlorine because:
A. Carbon easily becomes C⁴⁺
B. The bonds formed are weak
C. Carbon forms strong covalent bonds with many elements
D. Carbon has low electronegativity
Answer: C
Explanation: Carbon forms strong covalent bonds due to small size and valency 4.
Q8.
Which statement correctly describes why carbon rarely forms ionic bonds?
A. Carbon cannot share electrons
B. Carbon already has 8 valence electrons
C. Losing or gaining 4 electrons is not energetically favourable
D. Carbon forms metallic bonds instead
Answer: C
Explanation: Gaining or losing 4 electrons requires very high energy, so carbon prefers covalent bonding.
Q9.
Carbon forms millions of compounds, whereas silicon forms only a few, mainly because:
A. Silicon is more electronegative
B. Silicon atoms are too large to form stable chains
C. Silicon forms ionic bonds
D. Silicon has valency 2
Answer: B
Explanation: Silicon’s large atomic size makes its bonds weaker, so long chains are unstable.
Q10.
Which statement about carbon chains is correct?
A. All chains must be straight
B. Chains can be straight, branched, or cyclic
C. Chains can only contain hydrogen
D. Chains cannot contain double bonds
Answer: B
Explanation: Carbon chains may be straight, branched, or rings, with single, double, or triple bonds.
Q11.
The ability of carbon to form strong bonds with many elements leads to:
A. Instability of carbon compounds
B. Very few carbon compounds
C. A huge variety of stable organic compounds
D. Weak interaction with other atoms
Answer: C
Explanation: Strong covalent bonding with elements like H, O, N, and Cl allows carbon to form numerous stable compounds.
Q12.
Why does carbon readily form four covalent bonds?
A. It wants to become C²⁺
B. It needs four electrons to complete its octet
C. It has 8 electrons
D. It undergoes radioactive decay
Answer: B
Explanation: Carbon has 4 valence electrons and needs 4 more to complete its octet, so it forms four covalent bonds.
Versatiley
Saturated & Unsaturated Carbon Compounds
Q1. Saturated hydrocarbons are those compounds that contain:
A. Only C–C single bonds
B. Only C–C double bonds
C. Only C–C triple bonds
D. No hydrogen atoms
Answer: A
Explanation: The chapter states that compounds with only single bonds between carbon atoms are saturated.
Q2. Ethene (C₂H₄) is classified as unsaturated because it contains:
A. A C–C single bond
B. A C–C double bond
C. A C–C triple bond
D. No carbon–carbon bond
Answer: B
Explanation: Ethene has one double bond between carbon atoms.
Q3. Which compound contains a triple bond between carbon atoms?
A. Ethane
B. Ethene
C. Ethyne
D. Propane
Answer: C
Explanation: Ethyne (C₂H₂) contains a triple bond as shown in its electron-dot structure.
Q4. The general property of unsaturated compounds compared to saturated ones is that they are:
A. Less reactive
B. Colourless
C. More reactive
D. Unable to form chains
Answer: C
Explanation: Unsaturated compounds with double or triple bonds are more reactive than saturated ones.
Q5. In drawing structures of simple carbon compounds, the first step is to:
A. Add hydrogen atoms
B. Draw all bonds as triple bonds
C. Link carbon atoms with a single bond
D. Add functional groups
Answer: C
Explanation: The chapter shows that we begin by linking the carbon atoms with single bonds first.
Q6. Which statement is correct about saturated hydrocarbons like ethane?
A. They have remaining valencies satisfied by hydrogen
B. They cannot react with hydrogen
C. They contain double bonds
D. They are unstable
Answer: A
Explanation: After linking carbon atoms, remaining valencies are filled with hydrogen atoms, as shown in ethane.
Q7. Ethane (C₂H₆) is an example of:
A. Alkene
B. Alkyne
C. Saturated hydrocarbon
D. Aromatic hydrocarbon
Answer: C
Explanation: Ethane contains only single C–C and C–H bonds and is a saturated hydrocarbon.
Q8. Unsaturated compounds such as ethene and ethyne differ from saturated compounds by having:
A. Ionic bonds
B. Double or triple bonds
C. No hydrogen atoms
D. Metallic bonding
Answer: B
Explanation: The chapter defines unsaturated carbon compounds as those containing double or triple bonds.
Q9. Which formula corresponds to an unsaturated hydrocarbon?
A. C₂H₆
B. C₃H₈
C. C₂H₄
D. CH₄
Answer: C
Explanation: C₂H₄ (ethene) contains a double bond, making it unsaturated.
Q10. Why can’t the valencies of the carbon atoms in C₂H₄ be satisfied by a single C–C bond?
A. Because carbon cannot form single bonds
B. One valency per carbon remains unfilled
C. Carbon forms only triple bonds
D. Hydrogen cannot bond to carbon
Answer: B
Explanation: After forming a single bond, one valency remains unsatisfied on each carbon, requiring a double bond.
Q11. Which statement correctly describes the structure of ethane?
A. Both carbons form double bonds
B. Each carbon is bonded to three hydrogens
C. There is a triple bond between two carbons
D. It contains no hydrogen atoms
Answer: B
Explanation: Ethane’s structure shows each carbon bonded to three hydrogen atoms after forming the single C–C bond.
Q12. The electron dot structure of ethene shows:
A. All single bonds
B. One double bond between carbon atoms
C. A triple bond between carbon atoms
D. No C–H bonds
Answer: B
Explanation: The dot structure on page 64 illustrates one double bond in ethene.
SATURATED & UNSATURATED
Chains, Branches & Rings And Structural Isomerism
Q1.
The compound with the formula C₄H₁₀ exists in two different forms. These are known as:
A. Functional groups
B. Homologues
C. Structural isomers
D. Isotopes
Answer: C
Explanation: Page 65 of NCERT book shows two different structures for C₄H₁₀, both with the same formula but different arrangements—structural isomers.
Q2.
Which statement about carbon chains is correct?
A. They can only be straight
B. They can be straight, branched, or cyclic
C. They cannot form rings
D. They must always contain double bonds
Answer: B
Explanation: Carbon atoms can form straight chains, branched chains, and rings.
Q3.
Cyclohexane has the molecular formula:
A. C₆H₆
B. C₆H₁₂
C. C₆H₁₄
D. C₅H₁₂
Answer: B
Explanation: Page 65 of NCERT book shows cyclohexane with formula C₆H₁₂.
Q4.
Which structure represents a cyclic hydrocarbon?
A. CH₃–CH₂–CH₃
B. CH₃–CH₂–CH₂–CH₃
C. A hexagonal ring made of 6 carbons
D. CH₃–CH=CH₂
Answer: C
Explanation: The diagram on page 65 shows a ring of six carbons representing cyclohexane.
Q5.
In the branched-chain isomer of butane shown in the chapter, the branch occurs because:
A. One hydrogen is replaced by oxygen
B. A carbon atom is bonded to three other carbons
C. All bonds become double bonds
D. Carbon cannot form straight chains
Answer: B
Explanation: The page 65 structure shows the branched chain where one carbon is attached to three other carbons, forming isobutane.
Q6.
Which of the following is NOT an example of a cyclic compound?
A. Cyclohexane
B. Benzene
C. Propane
D. A six-carbon ring
Answer: C
Explanation: Propane is a straight-chain hydrocarbon, not cyclic. Cyclohexane and benzene are cyclic as shown in the text.
Q7.
Benzene (C₆H₆) contains:
A. Only single bonds
B. A ring with alternating double bonds
C. A straight-chain skeleton
D. A branched-chain skeleton
Answer: B
Explanation: The benzene structure in the chapter shows a ring with alternating double bonds.
Q8.
Which feature of carbon leads to the formation of branched and ring structures?
A. Its ability to form ionic bonds
B. Its ability to catenate
C. Its high atomic mass
D. Its ability to lose electrons
Answer: B
Explanation: Carbon’s catenation allows it to form long chains, branched structures, and rings.
Q9.
How many different structural isomers of C₄H₁₀ are shown in the chapter?
A. 1
B. 2
C. 3
D. 4
Answer: B
Explanation: Page 65 shows two different C₄H₁₀ structures—normal butane and isobutane.
Q10.
The molecular formula of benzene is:
A. C₆H₁₂
B. C₆H₆
C. C₅H₁₀
D. C₄H₁₀
Answer: B
Explanation: Figure 4.10 shows benzene = C₆H₆ with alternating double bonds.
Q11.
Which of the following pairs has the same molecular formula but different structures?
A. Benzene and cyclohexane
B. Butane and isobutane
C. Ethane and ethene
D. Propane and propene
Answer: B
Explanation: Only butane and isobutane share formula C₄H₁₀ but differ structurally.
Q12.
The straight-chain structure of butane contains:
A. 3 carbon atoms
B. 4 carbon atoms
C. 5 carbon atoms
D. 6 carbon atoms
Answer: B
Explanation: The straight-chain butane shown has 4 carbon atoms linked in a row.
CHAINS
Functional Groups
Q1.
A functional group is defined in the chapter as:
A. A carbon atom bonded to hydrogen
B. A specific atom or group of atoms replacing hydrogen in a carbon chain
C. Any random atom present in a compound
D. A compound with only carbon and hydrogen
Answer: B
Explanation: Functional groups are heteroatoms or groups replacing hydrogen in a carbon chain, giving the compound specific properties.
Q2.
Which of the following is a functional group?
A. –OH
B. –CO₂
C. –ClO
D. –NH₄
Answer: A
Explanation: –OH is the functional group of alcohols.
Q3.
The functional group present in aldehydes is represented as:
A. –OH
B. –COOH
C. –CHO
D. –Cl
Answer: C
Explanation: –CHO is the functional group of aldehydes.
Q4.
Which element commonly acts as a heteroatom in carbon compounds?
A. Helium
B. Neon
C. Oxygen
D. Argon
Answer: C
Explanation: The chapter lists oxygen, nitrogen, sulphur, chlorine, bromine as common heteroatoms.
Q5.
The functional group in carboxylic acids is:
A. –CO
B. –COOH
C. –C≡C–
D. –CH₃
Answer: B
Explanation: –COOH is the group characterising carboxylic acids.
Q6.
The functional group in ketones is written as:
A. –CO–
B. –OH
C. –COOH
D. –Cl
Answer: A
Explanation: –CO– (carbonyl group) is the functional group for ketones.
Q7.
Haloalkanes contain which type of functional group?
A. –OH
B. –CHO
C. –Cl or –Br
D. –COO–
Answer: C
Explanation: Halogen atoms like –Cl and –Br replace hydrogen in a carbon chain in haloalkanes.
Q8.
In carbon compounds, functional groups influence:
A. Only physical properties
B. Only boiling point
C. Chemical properties of the compound
D. Number of carbon atoms
Answer: C
Explanation: The chapter states functional groups decide the chemical properties, regardless of carbon chain length.
Q9.
Chloropropane belongs to which class of compounds?
A. Alcohol
B. Haloalkane
C. Ketone
D. Aldehyde
Answer: B
Explanation: “chloropropane” is under haloalkanes, with –Cl replacing hydrogen.
Q10.
Which functional group is present in propanone?
A. –OH
B. –CHO
C. –CO–
D. –COOH
Answer: C
Explanation: propanone under ketones, containing the carbonyl (–CO–) group.
Q11.
Which statement correctly describes a heteroatom?
A. It is always carbon
B. It replaces one or more hydrogens in a carbon chain
C. It cannot influence properties
D. It must be a noble gas
Answer: B
Explanation: Heteroatoms like O, N, S, Cl replace hydrogen while keeping the valency of carbon satisfied.
Q12.
Which compound contains the –OH functional group?
A. Propanal
B. Propanol
C. Bromopropane
D. Propanone
Answer: B
Explanation: propanol is under alcohols, containing the –OH group.
FUNCTIONAL
Homologous Series
Q1.
A homologous series is defined as a group of organic compounds that:
A. Have increasing atomic numbers
B. Have different functional groups
C. Have the same functional group and differ by –CH₂– units
D. Have the same number of carbon atoms
Answer: C
Explanation: The chapter states that members of a homologous series differ by –CH₂– units and have the same functional group.
Q2.
The difference between the molecular formula of ethane (C₂H₆) and propane (C₃H₈) is:
A. –H₂
B. –O
C. –CH₂
D. –COOH
Answer: C
Explanation: Successive members of a homologous series differ by –CH₂–. Ethane → Propane differs by –CH₂–.
Q3.
Which of the following belongs to the same homologous series as C₂H₅OH?
A. CH₄
B. C₃H₇OH
C. C₂H₂
D. C₄H₆
Answer: B
Explanation: Alcohols like CH₃OH, C₂H₅OH, C₃H₇OH all have the –OH functional group and differ by –CH₂– units.
Q4.
In the alkene homologous series, the general formula is:
A. CₙH₂ₙ₊₂
B. CₙH₂ₙ
C. CₙH₂ₙ₋₂
D. CₙHₙ
Answer: B
Explanation: The chapter states that alkenes like ethene (C₂H₄), propene (C₃H₆), butene (C₄H₈) follow CₙH₂ₙ.
Q5.
Which pair of compounds shows the correct difference of one –CH₂– unit?
A. CH₄ and C₂H₂
B. C₂H₆ and C₃H₈
C. C₂H₄ and C₄H₁₀
D. C₂H₆ and C₂H₄
Answer: B
Explanation: Ethane (C₂H₆) and propane (C₃H₈) differ by –CH₂–, matching the rule of homologous series.
Q6.
Members of a homologous series show a gradual change in:
A. Chemical properties
B. Functional groups
C. Physical properties
D. Number of elements present
Answer: C
Explanation: The chapter states that physical properties (melting/boiling points, solubility) show gradation. Chemical properties remain similar due to the same functional group.
Q7.
Which property remains similar for all members of a homologous series?
A. Melting point
B. Boiling point
C. Chemical properties
D. Density
Answer: C
Explanation: Chemical properties depend on the functional group, which remains the same for all members.
Q8.
Butene (C₄H₈) belongs to the same homologous series as:
A. C₂H₆
B. C₂H₄
C. C₂H₂
D. CH₃OH
Answer: B
Explanation: Both C₂H₄ (ethene) and C₄H₈ (butene) follow the alkene formula CₙH₂ₙ.
Q9.
Which of the following pairs belongs to different homologous series?
A. CH₄ and C₂H₆
B. C₂H₄ and C₃H₆
C. C₂H₅OH and C₃H₇OH
D. C₂H₆ and C₂H₄
Answer: D
Explanation: C₂H₆ is an alkane, C₂H₄ is an alkene—different series with different formulas and properties.
Q10.
Which characteristic is NOT true for a homologous series?
A. Same functional group
B. Difference of –CH₂– between successive members
C. Similar chemical properties
D. All members have identical molecular mass
Answer: D
Explanation: Molecular mass increases as the number of carbon atoms increases.
Q11.
The general formula for alkanes (as implied in the chapter) is:
A. CₙH₂ₙ
B. CₙH₂ₙ₋₂
C. CₙH₂ₙ₊₂
D. CₙHₙ
Answer: C
Explanation: From examples like CH₄, C₂H₆, C₃H₈, the implied general formula is CₙH₂ₙ₊₂.
Q12.
Members of a homologous series have:
A. Random functional groups
B. No relation between formulas
C. Predictable composition based on a general formula
D. Completely different chemical behaviours
Answer: C
Explanation: Each homologous series follows a general formula (e.g., alkanes: CₙH₂ₙ₊₂).
HOMOLOGOUS
Nomenclature of Carbon Compounds
Q1.
The first step in naming a carbon compound is to:
A. Identify the functional group
B. Count the number of carbon atoms in the chain
C. Check reactivity
D. Look for double bonds only
Answer: B
Explanation: Naming begins by identifying the number of carbon atoms in the longest chain.
Q2.
The suffix –ol in the IUPAC name indicates the presence of which functional group?
A. Aldehyde
B. Carboxylic acid
C. Alcohol
D. Ketone
Answer: C
Explanation: alcohols has the suffix –ol (e.g., propanol).
Q3.
Which is the correct IUPAC name for CH₃–CH₂–Br?
A. Bromoethane
B. Ethanol
C. Ethanal
D. Ethanoic acid
Answer: A
Explanation: The chapter directly names CH₃–CH₂–Br as bromoethane, with –Br as a prefix.
Q4.
When the suffix of a functional group begins with a vowel, the name of the carbon chain is modified by:
A. Adding “hydro–”
B. Adding an extra syllable
C. Removing the final “e” before adding the suffix
D. Removing the functional group
Answer: C
Explanation: For example, propane → propan + “one” = propanone. The final “e” is removed.
Q5.
Which compound is named propanal?
A. An aldehyde with three carbon atoms
B. An alcohol with three carbon atoms
C. A ketone with three carbon atoms
D. An alkyne with three carbons
Answer: A
Explanation: aldehydes take the suffix –al, so a 3-carbon aldehyde = propanal.
Q6.
What is the correct suffix for a carboxylic acid in IUPAC nomenclature?
A. –al
B. –one
C. –oic acid
D. –ene
Answer: C
Explanation:carboxylic acids use the suffix –oic acid, e.g., propanoic acid.
Q7.
If a carbon chain contains a double bond, the “–ane” suffix is replaced by:
A. –al
B. –ol
C. –ene
D. –one
Answer: C
Explanation: alkenes use the suffix –ene, e.g., propene.
Q8.
If a compound contains a triple bond, the suffix used is:
A. –ane
B. –yne
C. –one
D. –al
Answer: B
Explanation: alkynes use the suffix –yne, e.g., propyne.
Q9.
The compound with the structural formula
CH₃–CO–CH₃
is named:
A. Propanal
B. Propanol
C. Propanone
D. Propanoic acid
Answer: C
Explanation: The structure contains a ketone group, and the chapter names it propanone.
Q10.
Which prefix is used for a halogen substituent such as chlorine?
A. –ol
B. –al
C. Chloro–
D. Keto–
Answer: C
Explanation:“chloro–” is used for haloalkanes, such as chloropropane.
Q11.
The IUPAC name of the compound
CH₃–CH₂–CH₂–OH
is:
A. Propanal
B. Propanol
C. Propanone
D. Propanoic acid
Answer: B
Explanation: This is a three-carbon alcohol, so the name is propanol.
Q12.
What is the IUPAC name for the following compound shown in the chapter?
(a bromine atom attached to a 5-carbon chain)
A. Bromobutane
B. Bromopentane
C. Pentanol
D. Pentanone
Answer: B
Explanation: Page 69 lists bromopentane, with the –Br group on a 5-carbon chain.
IUPAC
Chemical Properties of Carbon Compounds
Q1.
Which product is always formed when carbon or its compounds undergo complete combustion?
A. Carbon monoxide
B. Carbon dioxide
C. Methane
D. Ethanol
Answer: B
Explanation: The chapter states carbon and its compounds burn in oxygen to give carbon dioxide with heat and light.
Q2.
Unsaturated hydrocarbons generally burn with:
A. A clean blue flame
B. No flame
C. A yellow sooty flame
D. A green flame
Answer: C
Explanation: Unsaturated hydrocarbons give a yellow flame with black smoke, forming soot.
Q3.
Which factor causes even saturated hydrocarbons to burn with a sooty flame?
A. Excess oxygen
B. Limited supply of air
C. High temperature
D. Presence of metal ions
Answer: B
Explanation: Page 70 states limited air supply leads to incomplete combustion, giving a sooty flame even for saturated compounds.
Q4.
Which substance is used as an oxidising agent for converting alcohols to acids?
A. Sodium chloride
B. Alkaline potassium permanganate
C. Sodium hydroxide
D. Copper sulphate
Answer: B
Explanation: The chapter states alkaline KMnO₄ or acidified K₂Cr₂O₇ oxidises alcohols to acids.
Q5.
Hydrogenation of vegetable oils requires:
A. Nickel as a catalyst
B. Oxygen gas
C. High voltage
D. Sodium metal
Answer: A
Explanation: Unsaturated oils add hydrogen in the presence of palladium or nickel to form saturated oils.
Q6.
Hydrogenation converts:
A. Saturated oils → Unsaturated oils
B. Unsaturated oils → Saturated oils
C. Carboxylic acids → Alcohols
D. Ketones → Aldehydes
Answer: B
Explanation: The chapter explains hydrogenation adds hydrogen to unsaturated oils, making them saturated.
Q7.
The reaction in which chlorine replaces hydrogen in a hydrocarbon (in sunlight) is called:
A. Addition reaction
B. Oxidation reaction
C. Substitution reaction
D. Reduction reaction
Answer: C
Explanation: The chapter states chlorine replaces hydrogen in saturated hydrocarbons in sunlight—substitution reaction.
Q8.
Which equation represents a substitution reaction?
A. CH₄ + Cl₂ → CH₃Cl + HCl
B. C₂H₄ + H₂ → C₂H₆
C. CH₃CH₂OH + O₂ → CO₂ + H₂O
D. C + O₂ → CO₂
Answer: A
Explanation: Chlorine replaces hydrogen in methane, forming CH₃Cl and HCl.\
Q9.
In an addition reaction involving unsaturated hydrocarbons:
A. Hydrogen atoms are removed
B. Two molecules combine to form one
C. A hydrogen molecule joins across a double or triple bond
D. A hydrogen atom is substituted by chlorine
Answer: C
Explanation: Hydrogen adds across double/triple bonds in unsaturated hydrocarbons.
Q10.
Vegetable oils are considered “healthier” because they generally contain:
A. Saturated fatty acids
B. Unsaturated fatty acids
C. No carbon atoms
D. Only aromatic rings
Answer: B
Explanation: The chapter states vegetable oils contain unsaturated fatty acids, while animal fats have saturated ones.
Q11.
Which gas is evolved when sodium reacts with ethanol?
A. Oxygen
B. Carbon dioxide
C. Hydrogen
D. Nitrogen
Answer: C
Explanation: Sodium reacts with ethanol to form sodium ethoxide and hydrogen gas is released.
Q12.
Which observation indicates incomplete combustion?
A. Blue flame
B. No flame
C. Soot deposition
D. Condensed water droplets
Answer: C
Explanation: Soot forms due to incomplete combustion and appears as black deposits (page 70).
CHEMICAL
Ethanol (Properties & Reactions)
Q1.
Ethanol is commonly known as:
A. Vinegar
B. Alcohol
C. Acetone
D. Formalin
Answer: B
Explanation: The chapter states that ethanol is commonly called alcohol and is the active ingredient of alcoholic drinks.
Q2.
Which statement about ethanol is correct ?
A. It is a solid at room temperature
B. It is insoluble in water
C. It is a liquid at room temperature
D. It is poisonous only in large amounts
Answer: C
Explanation: Ethanol is described as a liquid at room temperature with complete miscibility in water.
Q3.
What happens when a small piece of sodium is added to ethanol?
A. No reaction occurs
B. Hydrogen gas is evolved
C. Carbon dioxide is produced
D. Ethanol changes to ethene
Answer: B
Explanation: Ethanol reacts with sodium to produce sodium ethoxide and hydrogen gas.
Q4.
In the reaction of ethanol with sodium, the product other than hydrogen is:
A. Sodium acetate
B. Sodium ethoxide
C. Sodium chloride
D. Ethanoic acid
Answer: B
Explanation: The reaction forms sodium ethoxide, as shown in the given equation 2Na + 2CH₃CH₂OH → 2CH₃CH₂O⁻Na⁺ + H₂.
Q5.
Which agent removes water from ethanol during dehydration?
A. Sodium chloride
B. Concentrated sulphuric acid
C. Potassium permanganate
D. Sodium hydroxide
Answer: B
Explanation: Heating ethanol with concentrated sulphuric acid at 443 K removes water, forming ethene.
Q6.
Dehydration of ethanol produces:
A. Ethanoic acid
B. Ethyne
C. Ethene
D. Methane
Answer: C
Explanation: The chapter’s equation shows:
Ethanol → (hot conc. H₂SO₄, 443 K) → Ethene + Water.
Q7.
Ethanol is added to some industrial products along with dyes to make it unfit for drinking. This is known as:
A. Oxidation
B. Saponification
C. Denaturation
D. Hydrogenation
Answer: C
Explanation:Ethanol is made unfit for drinking by adding toxic substances and dyes—called denatured alcohol.
Q8.
What is the harmful effect of drinking pure ethanol (absolute alcohol)?
A. Causes no effect
B. Causes mild dizziness only
C. Can be lethal even in small quantity
D. Converts into fat
Answer: C
Explanation: The chapter warns that even a small quantity of absolute alcohol is lethal.
Q9.
Ethanol is used in tincture iodine because it is a good:
A. Oxidising agent
B. Solvent
C. Acid
D. Base
Answer: B
Explanation: Ethanol is used in medicines (e.g., tincture iodine) because it is a good solvent.
Q10.
Excessive long-term consumption of ethanol leads to:
A. Stronger metabolism
B. Improved brain function
C. Health problems including damage to organs
D. No medical issues
Answer: C
Explanation: The chapter states long-term consumption of ethanol leads to many health problems.
Q11.
Methanol poisoning occurs because methanol is oxidised in the liver to:
A. Ethanoic acid
B. Methanal
C. Carbon monoxide
D. Methane
Answer: B
Explanation: Methanol is oxidised to methanal, which coagulates cell components and damages optic nerves.
Q12.
The reaction that converts ethanol to ethene is classified as:
A. Addition
B. Oxidation
C. Substitution
D. Dehydration
Answer: D
Explanation: Removing water from ethanol using conc. H₂SO₄ at 443 K is a dehydration reaction.
Ethanaol
Ethanoic Acid (Properties & Reactions)
Q1.
Ethanoic acid is commonly known as:
A. Alcohol
B. Vinegar
C. Acetone
D. Ether
Answer: B
Explanation: A 5–8% solution of ethanoic acid in water is called vinegar.
Q2.
A unique physical property of pure ethanoic acid is that it:
A. Does not dissolve in water
B. Turns solid at room temperature
C. Freezes during cold climates
D. Burns with a sooty flame
Answer: C
Explanation: The melting point of pure ethanoic acid is 290 K, so it often freezes in winter—hence called glacial acetic acid.
Q3.
Ethanoic acid belongs to which class of organic compounds?
A. Alcohols
B. Ketones
C. Carboxylic acids
D. Aldehydes
Answer: C
Explanation: Ethanoic acid contains the –COOH group, characteristic of carboxylic acids.
Q4.
Compared to dilute hydrochloric acid, ethanoic acid is:
A. A stronger acid
B. A weaker acid
C. Neutral
D. A base
Answer: B
Explanation: The chapter notes that carboxylic acids like ethanoic acid are weak acids, unlike completely ionised mineral acids such as HCl.
Q5.
Ethanoic acid reacts with ethanol in the presence of a few drops of concentrated H₂SO₄ to form:
A. Acetaldehyde
B. Soap
C. An ester
D. Ethyne
Answer: C
Explanation: Ethanoic acid + ethanol → ester (sweet-smelling) in the presence of acid catalyst.
Q6.
The reaction between ethanoic acid and ethanol is known as:
A. Hydrogenation
B. Oxidation
C. Saponification
D. Esterification
Answer: D
Explanation: The reaction producing an ester from an acid and alcohol is esterification.
Q7.
When the ester formed from ethanoic acid is treated with sodium hydroxide, it gives:
A. Alcohol + sodium salt of carboxylic acid
B. Ketone + CO₂
C. Ammonia + alcohol
D. Aldehyde + hydrogen
Answer: A
Explanation: Ester + NaOH → Alcohol + sodium salt of carboxylic acid (saponification).
Q8.
Ethanoic acid reacts with sodium carbonate to produce:
A. Sodium chloride
B. Hydrogen gas
C. Carbon dioxide
D. Methane
Answer: C
Explanation: Ethanoic acid + sodium carbonate → sodium ethanoate + CO₂ + water.
Q9.
Which observation confirms the presence of carbon dioxide when ethanoic acid reacts with sodium carbonate?
A. Yellow flame
B. Popping sound
C. Formation of scum
D. Turning limewater milky
Answer: D
Explanation: The chapter describes passing the gas into limewater, which turns milky, confirming CO₂.
Q10.
Ethanoic acid reacts with sodium hydrogencarbonate to form:
A. Sodium acetate + water + CO₂
B. Sodium hydroxide + hydrogen
C. Ethanol + sodium
D. Methane + water
Answer: A
Explanation: CH₃COOH + NaHCO₃ → CH₃COONa + H₂O + CO₂.
Q11.
Which test can distinguish ethanoic acid from ethanol?
A. Reaction with sodium metal
B. Reaction with water
C. Reaction with ethene
D. Reaction with sodium hydrogencarbonate
Answer: D
Explanation: Ethanoic acid reacts with NaHCO₃ to produce CO₂ (effervescence). Ethanol does not.
Q12.
Why does ethanoic acid show acidic properties?
A. It forms strong ionic bonds
B. It completely dissociates in water
C. It releases H⁺ ions in solution
D. It contains only hydrogen
Answer: C
Explanation: Carboxylic acids are weak acids because they partially ionise to release H⁺ ions.
Ethanoic
Soaps And Detergents
Q1.
A soap molecule consists of:
A. A hydrophobic head and hydrophilic tail
B. A hydrophilic head and hydrophobic tail
C. Two hydrophilic ends
D. Two hydrophobic ends
Answer: B
Explanation: The soap molecule has a hydrophobic hydrocarbon tail and a hydrophilic ionic head.
Q2.
The hydrophobic tail of a soap molecule is:
A. Attracted to oil and grease
B. Attracted to water
C. Repelled by oil
D. Positively charged
Answer: A
Explanation: The hydrocarbon tail is water-repelling but attracted to oil/grease, helping remove dirt.
Q3.
The cleansing action of soap is mainly due to the formation of:
A. Salts
B. Micelles
C. Detergent bubbles
D. Alcohols
Answer: B
Explanation: Soap forms micelles, where tails trap dirt/oil inside and the head stays in water.
Q4.
In a micelle, the soap molecules arrange themselves such that:
A. Hydrophobic tails point outward
B. Hydrophilic heads point inward
C. Hydrophobic tails point inward
D. All parts face the same direction
Answer: C
Explanation: In micelles, hydrophobic tails cluster inside around dirt, and hydrophilic heads face water.
Q5.
Soaps do NOT work well in hard water because:
A. They evaporate quickly
B. They react with calcium and magnesium salts
C. They dissolve completely
D. They form micelles too easily
Answer: B
Explanation: Hard water contains Ca²⁺ and Mg²⁺ ions, which form insoluble precipitates with soap.
Q6.
The insoluble precipitate formed when soap reacts with calcium/magnesium ions is called:
A. Micelle
B. Scum
C. Foam
D. Esters
Answer: B
Explanation: The reaction of soap with Ca²⁺/Mg²⁺ forms scum, which reduces cleansing ability.
Q7.
Which cleansing agent is more effective in hard water?
A. Soap
B. Detergent
C. Ethanol
D. Ethanoic acid
Answer: B
Explanation: Detergents do not form scum with Ca²⁺ or Mg²⁺ ions, so they work better in hard water.
Q8.
Which statement about detergents is correct according to the chapter?
A. They are fully biodegradable
B. They work only in soft water
C. They do not react with hard-water ions
D. They cannot form micelles
Answer: C
Explanation: Detergents do not form precipitates with hard-water ions, making them effective cleansers.
Q9.
Detergents cause environmental problems mainly because they:
A. Are too soluble
B. Form scum
C. Are often non-biodegradable
D. Evaporate slowly
Answer: C
Explanation: The chapter mentions many detergents are non-biodegradable, creating environmental pollution.
Q10.
When soap is used in soft water, the cleansing action improves because soft water:
A. Contains more ions
B. Does not contain Ca²⁺ or Mg²⁺
C. Forms scum quickly
D. Has a lower boiling point
Answer: B
Explanation: Soft water lacks Ca²⁺/Mg²⁺, preventing scum formation and allowing better cleansing.
Q11.
In the diagram of soap micelle formation, the dirt is located:
A. Outside the micelle
B. Between the ionic heads
C. Inside the cluster of hydrophobic tails
D. In the water layer
Answer: C
Explanation: The micelle diagram shows dirt trapped at the centre, held by hydrophobic tails.
Q12.
The ionic (hydrophilic) end of a soap molecule is attracted to:
A. Oil
B. Dirt
C. Water
D. Grease
Answer: C
Explanation: The ionic head is water-attracting, allowing the micelle to remain suspended in water.!
