Class 11 Chemistry MCQ Chapter 12 Organic Chemistry – Some Basic Principles and Techniques
Looking for Class 11 Chemistry MCQ Chapter 12 Organic Chemistry – Some Basic Principles and Techniques English Medium? You have come to the right place. This article provides important MCQ questions with answers that will help AHSEC Higher Secondary First Year students build a strong foundation in Organic Chemistry.
The chapter Organic Chemistry – Some Basic Principles and Techniques introduces students to the basic concepts of organic compounds and their classification. It covers important topics such as the tetravalency of carbon, structural formulas, homologous series, nomenclature of organic compounds, isomerism, electronic displacement effects, purification methods, and qualitative as well as quantitative analysis of organic substances. These concepts are essential for understanding advanced organic chemistry chapters.
All MCQs are prepared according to the latest AHSEC syllabus and examination pattern. The questions are designed to help students revise key concepts, improve their problem-solving skills, and become familiar with exam-oriented objective questions.
Whether you are preparing for class tests, annual examinations, or the AHSEC HS First Year Final Examination, these MCQ solutions will help you strengthen your concepts and perform better in Chemistry.
Part II
Organic Chemistry – Some Basic Principles and Techniques
Selected VSA & MCQ
I. Very Short Answer Questions (VSA)
Q: What is organic chemistry?
Ans: Organic chemistry is the branch of chemistry that deals with the study of carbon
compounds except carbonates, bicarbonates, cyanides and oxides of carbon.
Q: Why does carbon form a large number of compounds?
Ans: Carbon forms a large number of compounds due to catenation and tetravalency.
Q: What is catenation?
Ans: Catenation is the property of carbon to form chains and rings by bonding with
itself.
Q: What is tetravalency of carbon?
Ans: Tetravalency of carbon is the property by which carbon forms four covalent bonds.
Q: What are hydrocarbons?
Ans: Hydrocarbons are compounds containing only carbon and hydrogen.
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 is a functional group?
Ans: A functional group is an atom or group of atoms responsible for the characteristic
properties of an organic compound.
Q: Give one example of a functional group.
Ans: The hydroxyl group ((-OH)) is a functional group.
Q: What is isomerism?
Ans: Isomerism is the phenomenon in which compounds have the same molecular
formula but different structures or properties.
Q: What are structural isomers?
Ans: Structural isomers are compounds having the same molecular formula but different
structural formulas.
Q: What is chain isomerism?
Ans: Chain isomerism arises due to different arrangements of carbon chains.
Q: What is position isomerism?
Ans: Position isomerism arises due to different positions of functional groups or multiple
bonds.
Q: What is functional isomerism?
Ans: Functional isomerism arises when compounds have the same molecular formula
but different functional groups.
Q: What is nomenclature?
Ans: Nomenclature is the system of naming chemical compounds according to IUPAC
rules.
Q: What does IUPAC stand for?
Ans: IUPAC stands for International Union of Pure and Applied Chemistry.
Q: What is the suffix used for alcohols in IUPAC nomenclature?
Ans: The suffix used for alcohols is “-ol”.
Q: What is the suffix used for aldehydes?
Ans: The suffix used for aldehydes is “-al”.
Q: What is the suffix used for carboxylic acids?
Ans: The suffix used for carboxylic acids is “-oic acid”.
Q: What are free radicals?
Ans: Free radicals are atoms or groups of atoms containing unpaired electrons.
Q: What is heterolytic fission?
Ans: Heterolytic fission is the breaking of a covalent bond in which one atom takes away
both bonding electrons.
Q: What is homolytic fission?
Ans: Homolytic fission is the breaking of a covalent bond in which each atom takes one
bonding electron.
Q: What is an electrophile?
Ans: An electrophile is an electron-deficient species that accepts electrons.
Q: What is a nucleophile?
Ans: A nucleophile is an electron-rich species that donates electrons.
Q: What is an organic reaction mechanism?
Ans: Organic reaction mechanism is the stepwise sequence through which an organic
reaction takes place.
Q: What is inductive effect?
Ans: Inductive effect is the permanent displacement of sigma electrons along a carbon
chain due to electronegativity difference.
Q: What is resonance?
Ans: Resonance is the phenomenon in which a molecule is represented by two or more
contributing structures differing only in the arrangement of electrons.
Q: What is hyperconjugation?
Ans: Hyperconjugation is the delocalisation of sigma electrons with adjacent pi bonds or
vacant orbitals.
Q: What is purification?
Ans: Purification is the process of removing impurities from organic compounds.
Q: Name one method of purification of organic compounds.
Ans: Crystallisation is a method of purification of organic compounds.
Q: What is sublimation?
Ans: Sublation is the process in which a solid changes directly into vapour without
passing through the liquid state.
Q: What is distillation?
Ans: Distillation is the process of separating liquids based on differences in boiling
points.
Q: What is chromatography?
Ans: Chromatography is a technique used for separation and identification of
components of a mixture.
Q: What is qualitative analysis?
Ans: Qualitative analysis is the method used to detect the elements present in an organic
compound.
Q: What is quantitative analysis?
Ans: Quantitative analysis is the method used to determine the percentage composition
of elements in an organic compound.
Q: Which element is detected by Lassaigne’s test?
Ans: Nitrogen, sulphur and halogens are detected by Lassaigne’s test.
Q: What is the purpose of sodium fusion test?
Ans: Sodium fusion test converts covalent compounds into ionic compounds for easy
detection.
Q: Why are organic compounds generally covalent?
Ans: Organic compounds are generally covalent because carbon forms covalent bonds
by sharing electrons.
Q: What is the main source of organic compounds?
Ans: Petroleum and natural gas are the main sources of organic compounds.
II. Multiple Choice Questions (MCQs)
Q: Organic chemistry mainly deals with the compounds of —
(a) Oxygen
(b) Nitrogen
(c) Carbon
(d) Sulphur
Ans: (c) Carbon
Q: Carbon forms a large number of compounds due to —
(a) Radioactivity
(b) Catenation and tetravalency
(c) High atomic mass
(d) Metallic character
Ans: (b) Catenation and tetravalency
Q: The property of self-linking of carbon atoms is called —
(a) Hybridisation
(b) Polymerisation
(c) Catenation
(d) Ionisation
Ans: (c) Catenation
Q: Tetravalency of carbon means carbon forms —
(a) Two bonds
(b) Three bonds
(c) Four bonds
(d) One bond
Ans: (c) Four bonds
Q: Hydrocarbons are compounds containing —
(a) Carbon and oxygen
(b) Carbon and nitrogen
(c) Carbon and hydrogen
(d) Carbon and sulphur
Ans: (c) Carbon and hydrogen
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: The group responsible for characteristic properties of an organic compound is
called —
(a) Radical
(b) Catalyst
(c) Functional group
(d) Isotope
Ans: (c) Functional group
Q: Isomerism is the phenomenon in which compounds have the same —
(a) Structural formula only
(b) Molecular formula but different structures
(c) Functional group only
(d) Physical state only
Ans: (b) Molecular formula but different structures
Q: Chain isomerism arises due to different —
(a) Functional groups
(b) Positions of double bonds
(c) Arrangements of carbon chains
(d) Molecular masses
Ans: (c) Arrangements of carbon chains
Q: Position isomerism arises due to different positions of —
(a) Carbon atoms only
(b) Functional groups or multiple bonds
(c) Hydrogen atoms only
(d) Oxygen atoms only
Ans: (b) Functional groups or multiple bonds
Q: Functional isomerism arises due to different —
(a) Carbon chains
(b) Molecular masses
(c) Functional groups
(d) Numbers of atoms
Ans: (c) Functional groups
Q: IUPAC stands for —
(a) International Union of Pure and Applied Chemistry
(b) Indian Union of Practical and Applied Chemistry
(c) International Union of Pure and Applied Chemistry
(d) Indian Universal Process of Analytical Chemistry
Ans: (c) International Union of Pure and Applied Chemistry
Q: The suffix used for alcohols is —
(a) -al
(b) -one
(c) -ol
(d) -oic acid
Ans: (c) -ol
Q: The suffix used for aldehydes is —
(a) -ol
(b) -al
(c) -one
(d) -yne
Ans: (b) -al
Q: The suffix used for carboxylic acids is —
(a) -al
(b) -ol
(c) -amine
(d) -oic acid
Ans: (d) -oic acid
Q: Free radicals contain —
(a) Paired electrons
(b) No electrons
(c) Unpaired electrons
(d) Only protons
Ans: (c) Unpaired electrons
Q: In homolytic fission, the bonded electrons are —
(a) Taken by one atom
(b) Equally shared between atoms
(c) Lost completely
(d) Gained by nucleus
Ans: (b) Equally shared between atoms
Q: In heterolytic fission, one atom takes —
(a) One electron
(b) No electron
(c) Both bonding electrons
(d) One proton
Ans: (c) Both bonding electrons
Q: An electrophile is a species that —
(a) Donates electrons
(b) Accepts electrons
(c) Donates protons
(d) Accepts neutrons
Ans: (b) Accepts electrons
Q: A nucleophile is a species that —
(a) Accepts electrons
(b) Donates electrons
(c) Accepts neutrons
(d) Releases protons
Ans: (b) Donates electrons
Q: The permanent displacement of sigma electrons is called —
(a) Resonance
(b) Hyperconjugation
(c) Inductive effect
(d) Hybridisation
Ans: (c) Inductive effect
Q: Resonance involves movement of —
(a) Atoms
(b) Sigma electrons
(c) Neutrons
(d) Electrons
Ans: (d) Electrons
Q: Hyperconjugation involves delocalisation of —
(a) Sigma electrons
(b) Pi electrons only
(c) Protons
(d) Neutrons
Ans: (a) Sigma electrons
Q: Which method is commonly used for purification of solid organic compounds?
(a) Distillation
(b) Sublimation
(c) Crystallisation
(d) Filtration
Ans: (c) Crystallisation
Q: Distillation is used to separate substances based on differences in —
(a) Density
(b) Colour
(c) Boiling points
(d) Solubility
Ans: (c) Boiling points
Q: Chromatography is mainly used for —
(a) Heating compounds
(b) Separation of mixtures
(c) Measuring mass
(d) Neutralisation
Ans: (b) Separation of mixtures
Q: Lassaigne’s test is used to detect —
(a) Carbon and hydrogen only
(b) Nitrogen, sulphur and halogens
(c) Oxygen only
(d) Metals only
Ans: (b) Nitrogen, sulphur and halogens
Q: Assertion (A): Carbon forms a large number of compounds.
Reason (R): Carbon shows catenation and tetravalency.
(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): Organic compounds are generally covalent.
Reason (R): Carbon forms covalent bonds by sharing electrons.
(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): Graphite conducts electricity.
Reason (R): Graphite contains delocalised electrons.
(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): Electrophiles are electron-deficient species.
Reason (R): Electrophiles accept electrons during reactions.
(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): Nucleophiles are electron-rich species.
Reason (R): Nucleophiles donate electron pairs.
(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): Distillation is used for purification of liquids.
Reason (R): Distillation separates substances based on boiling points.
(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): Lassaigne’s test is used in qualitative analysis of organic compounds.
Reason (R): Sodium fusion converts covalent compounds into ionic compounds.
(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. 0 0 0
