Class 11 Chemistry MCQ Chapter 13 Hydrocarbons
Are you preparing for your Chemistry exam and searching for Class 11 Chemistry MCQ Chapter 13 Hydrocarbons English Medium? Then this article is the perfect study material for you. Here, you will find important multiple-choice questions (MCQs) with answers specially prepared for AHSEC Higher Secondary First Year students.
The chapter Hydrocarbons deals with organic compounds that contain only carbon and hydrogen atoms. Students will learn about alkanes, alkenes, alkynes, aromatic hydrocarbons, their structures, properties, preparation methods, and chemical reactions. The chapter also explains important concepts such as isomerism, electrophilic substitution, addition reactions, and the uses of different hydrocarbons in daily life.
These MCQ questions are based on the latest AHSEC syllabus and examination pattern. Regular practice will help students understand important concepts, improve revision, and gain confidence in answering objective questions during examinations.
Whether you are studying for class tests, annual examinations, or the AHSEC HS First Year Final Examination, these MCQ solutions will help you strengthen your Organic Chemistry knowledge and achieve better academic results.
Part II
Class 11 Chemistry MCQ Chapter 13 Hydrocarbons
Selected VSA & MCQ
I. Very Short Answer Questions (VSA)
Q: What are hydrocarbons?
Ans: Hydrocarbons are organic compounds containing only carbon and hydrogen.
Q: Into how many classes are hydrocarbons broadly divided?
Ans: Hydrocarbons are broadly divided into aliphatic and aromatic hydrocarbons.
Q: What are aliphatic hydrocarbons?
Ans: Aliphatic hydrocarbons are hydrocarbons having open chain structures.
Q: What are aromatic hydrocarbons?
Ans: Aromatic hydrocarbons are hydrocarbons containing benzene ring structures.
Q: What are saturated hydrocarbons?
Ans: Saturated hydrocarbons are hydrocarbons containing only single covalent bonds between carbon atoms.
Q: What are unsaturated hydrocarbons?
Ans: Unsaturated hydrocarbons are hydrocarbons containing double or triple bonds between carbon atoms.
Q: What are alkanes?
Ans: Alkanes are saturated hydrocarbons containing only single covalent bonds.
Q: What are alkenes?
Ans: Alkenes are unsaturated hydrocarbons containing at least one double bond.
Q: What are alkynes?
Ans: Alkynes are unsaturated hydrocarbons containing at least one triple bond.
Q: What is marsh gas?
Ans: Methane is commonly known as marsh gas.
Q: Why is methane called marsh gas?
Ans: Methane is called marsh gas because it is produced in marshy areas due to decomposition of organic matter.
Q: What is natural gas mainly composed of?
Ans: Natural gas mainly consists of methane.
Q: What is LPG?
Ans: LPG is liquefied petroleum gas containing mainly propane and butane.
Q: What is CNG?
Ans: CNG is compressed natural gas used as a fuel.
Q: What is cracking?
Ans: Cracking is the process of breaking larger hydrocarbon molecules into smaller hydrocarbons.
Q: What is pyrolysis?
Ans: Pyrolysis is the decomposition of organic substances by heating in the absence of air.
Q: What is substitution reaction?
Ans: Substitution reaction is a reaction in which one atom or group in a compound is replaced by another atom or group.
Q: What is addition reaction?
Ans: Addition reaction is a reaction in which atoms are added to unsaturated compounds.
Q: Why do alkenes undergo addition reactions?
Ans: Alkenes undergo addition reactions due to the presence of double bonds.
Q: What is hydrogenation?
Ans: Hydrogenation is the addition of hydrogen to unsaturated hydrocarbons.
Q: Which catalyst is commonly used in hydrogenation?
Ans: Nickel catalyst is commonly used in hydrogenation.
Q: What is polymerisation?
Ans: Polymerisation is the process in which small molecules combine to form large molecules called polymers.
Q: What is the shape of benzene molecule?
Ans: Benzene molecule has a planar hexagonal structure.
Q: What type of reactions are shown by benzene?
Ans: Benzene mainly undergoes substitution reactions.
Q: Why does benzene resist addition reactions?
Ans: Benzene resists addition reactions due to resonance stability.
Q: What is resonance in benzene?
Ans: Resonance in benzene is the delocalisation of pi electrons over the benzene ring.
Q: What is aromaticity?
Ans: Aromaticity is the special stability shown by aromatic compounds due to delocalised electrons.
Q: Name one carcinogenic aromatic hydrocarbon.
Ans: Benzopyrene is a carcinogenic aromatic hydrocarbon.
Q: What is combustion reaction of hydrocarbons?
Ans: Combustion reaction is the burning of hydrocarbons in oxygen to produce carbon dioxide and water.
Q: Why are hydrocarbons used as fuels?
Ans: Hydrocarbons are used as fuels because they produce large amounts of heat on combustion.
Q: State one use of acetylene.
Ans: Acetylene is used in oxy-acetylene welding.
Q: Why is benzene called an aromatic compound?
Ans: Benzene is called an aromatic compound because of its characteristic aromatic odour and special stability.
II. Multiple Choice Questions (MCQs)
Q: Hydrocarbons are compounds containing —
(a) Carbon, hydrogen and oxygen
(b) Carbon and hydrogen only
(c) Carbon and nitrogen only
(d) Carbon and sulphur only
Ans: (b) Carbon and hydrogen only
Q: Hydrocarbons are broadly classified into —
(a) Saturated and unsaturated
(b) Organic and inorganic
(c) Aliphatic and aromatic
(d) Acidic and basic
Ans: (c) Aliphatic and aromatic
Q: Aliphatic hydrocarbons have —
(a) Benzene rings only
(b) Open chain structures
(c) Ionic structures
(d) Metallic structures
Ans: (b) Open chain structures
Q: Aromatic hydrocarbons contain —
(a) Triple bonds only
(b) Nitrogen atoms
(c) Benzene rings
(d) Oxygen atoms
Ans: (c) Benzene rings
Q: Saturated hydrocarbons contain only —
(a) Double bonds
(b) Triple bonds
(c) Single bonds
(d) Ionic bonds
Ans: (c) Single bonds
Q: Unsaturated hydrocarbons contain —
(a) Only single bonds
(b) Double or triple bonds
(c) Ionic bonds
(d) Hydrogen bonds
Ans: (b) Double or triple bonds
Q: Alkanes are —
(a) Unsaturated hydrocarbons
(b) Aromatic hydrocarbons
(c) Saturated hydrocarbons
(d) Cyclic compounds
Ans: (c) Saturated hydrocarbons
Q: Alkenes contain at least one —
(a) Single bond
(b) Double bond
(c) Triple bond
(d) Ionic bond
Ans: (b) Double bond
Q: Alkynes contain at least one —
(a) Single bond
(b) Double bond
(c) Triple bond
(d) Coordinate bond
Ans: (c) Triple bond
Q: The simplest alkane is —
(a) Ethane
(b) Propane
(c) Methane
(d) Butane
Ans: (c) Methane
Q: Methane is commonly known as —
(a) Coal gas
(b) Water gas
(c) Marsh gas
(d) Producer gas
Ans: (c) Marsh gas
Q: Natural gas mainly contains —
(a) Ethane
(b) Propane
(c) Butane
(d) Methane
Ans: (d) Methane
Q: LPG mainly contains —
(a) Methane and ethylene
(b) Propane and butane
(c) Ethane and acetylene
(d) Benzene and toluene
Ans: (b) Propane and butane
Q: CNG stands for —
(a) Compressed Natural Gas
(b) Combined Natural Gas
(c) Condensed Noble Gas
(d) Controlled Natural Gas
Ans: (a) Compressed Natural Gas
Q: Cracking is the process of —
(a) Joining small molecules
(b) Breaking larger hydrocarbons into smaller ones
(c) Purifying hydrocarbons
(d) Oxidising hydrocarbons
Ans: (b) Breaking larger hydrocarbons into smaller ones
Q: Pyrolysis means decomposition in the absence of —
(a) Water
(b) Catalyst
(c) Air
(d) Heat
Ans: (c) Air
Q: Chlorination of methane is an example of —
(a) Addition reaction
(b) Elimination reaction
(c) Substitution reaction
(d) Polymerisation reaction
Ans: (c) Substitution reaction
Q: Alkenes generally undergo —
(a) Substitution reactions
(b) Addition reactions
(c) Neutralisation reactions
(d) Double decomposition reactions
Ans: (b) Addition reactions
Q: Hydrogenation involves addition of —
(a) Oxygen
(b) Nitrogen
(c) Hydrogen
(d) Chlorine
Ans: (c) Hydrogen
Q: Which catalyst is commonly used for hydrogenation?
(a) Copper
(b) Zinc
(c) Nickel
(d) Iron
Ans: (c) Nickel
Q: Polymerisation is the process of formation of —
(a) Acids
(b) Polymers
(c) Salts
(d) Radicals
Ans: (b) Polymers
Q: The shape of benzene molecule is —
(a) Linear
(b) Tetrahedral
(c) Planar hexagonal
(d) Pyramidal
Ans: (c) Planar hexagonal
Q: Benzene mainly undergoes —
(a) Addition reactions
(b) Substitution reactions
(c) Decomposition reactions
(d) Neutralisation reactions
Ans: (b) Substitution reactions
Q: Benzene resists addition reactions because of —
(a) Ionic bonding
(b) Hydrogen bonding
(c) Resonance stability
(d) High molecular mass
Ans: (c) Resonance stability
Q: Delocalisation of pi electrons in benzene is called —
(a) Hybridisation
(b) Resonance
(c) Polymerisation
(d) Isomerism
Ans: (b) Resonance
Q: Acetylene is used in —
(a) Refrigeration
(b) Water purification
(c) Oxy-acetylene welding
(d) Electroplating
Ans: (c) Oxy-acetylene welding
Q: Assertion (A): Methane is called marsh gas.
Reason (R): Methane is produced in marshy areas due to decomposition of organic matter.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is not the correct explanation of A
(c) A is true but R is false
(d) A is false but R is true
Ans: (a) Both A and R are true and R is the correct explanation of A
Q: Assertion (A): Alkenes undergo addition reactions.
Reason (R): Alkenes contain carbon-carbon double bonds.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is not the correct explanation of A
(c) A is true but R is false
(d) A is false but R is true
Ans: (a) Both A and R are true and R is the correct explanation of A
Q: Assertion (A): Benzene mainly undergoes substitution reactions.
Reason (R): Benzene ring is stabilised by resonance.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is not the correct explanation of A
(c) A is true but R is false
(d) A is false but R is true
Ans: (a) Both A and R are true and R is the correct explanation of A
Q: Assertion (A): Hydrocarbons are used as fuels.
Reason (R): Hydrocarbons produce large amounts of heat on combustion.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is not the correct explanation of A
(c) A is true but R is false
(d) A is false but R is true
Ans: (a) Both A and R are true and R is the correct explanation of A
Q: Assertion (A): Benzene resists addition reactions.
Reason (R): Addition reactions destroy the resonance stability of benzene.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is not the correct explanation of A
(c) A is true but R is false
(d) A is false but R is true
Ans: (a) Both A and R are true and R is the correct explanation of A
Q: Assertion (A): Acetylene is an unsaturated hydrocarbon.
Reason (R): Acetylene contains a carbon-carbon triple bond.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is not the correct explanation of A
(c) A is true but R is false
(d) A is false but R is true
Ans: (a) Both A and R are true and R is the correct explanation of A
Q: Assertion (A): Cracking is important in petroleum industry.
Reason (R): Cracking converts heavy hydrocarbons into useful smaller hydrocarbons.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is not the correct explanation of A
(c) A is true but R is false
(d) A is false but R is true
Ans: (a) Both A and R are true and R is the correct explanation of A.
