Class 11 – Organic Chemistry: Some Basic Principles and Techniques (40 MCQs)
Introduction to Organic Chemistry (1–4)
- Organic chemistry primarily deals with compounds of:
a) Oxygen
b) Carbon
c) Nitrogen
d) Hydrogen - Which of the following is an organic compound?
a) NaCl
b) CH₄
c) CaCO₃
d) H₂O - Organic compounds are generally:
a) Ionic
b) Covalent
c) Metallic
d) Electrolytic - Which type of bonds is most common in organic compounds?
a) Ionic bonds
b) Covalent bonds
c) Hydrogen bonds
d) Metallic bonds
Methods of Preparation of Organic Compounds (5–10)
- Methane can be prepared by:
a) Wurtz reaction
b) Reduction of CO
c) Sabatier reaction
d) Friedel–Crafts reaction - Ethanol can be prepared by:
a) Fermentation of sugars
b) Hydrolysis of alkanes
c) Oxidation of aldehydes
d) Dehydration of carboxylic acids - Which reaction is used to prepare alkyl halides?
a) Halogenation
b) Hydrolysis
c) Dehydration
d) Oxidation - Which method is commonly used to prepare alkanes?
a) Wurtz reaction
b) Electrophilic addition
c) Nucleophilic substitution
d) Esterification - Preparation of benzene from acetylene involves:
a) Cyclization
b) Halogenation
c) Hydrogenation
d) Dehydration - Grignard reagent is prepared by:
a) Reaction of alkyl halide with Mg in dry ether
b) Halogenation of alkanes
c) Oxidation of alcohols
d) Reduction of aldehydes
Purification Techniques (11–17)
- Distillation is used to separate liquids based on:
a) Density
b) Solubility
c) Boiling points
d) Polarity - Fractional distillation is used when boiling points differ by:
a) >50°C
b) <25°C
c) 100°C
d) 0°C - Crystallization separates solids based on:
a) Solubility
b) Volatility
c) Density
d) Color - Sublimation is used to purify:
a) Soluble salts
b) Organic solids that sublime
c) Acids
d) Bases - Paper chromatography separates compounds based on:
a) Molecular weight
b) Differential solubility and adsorption
c) Boiling point
d) Density - Thin layer chromatography (TLC) uses:
a) Glass plates coated with adsorbent
b) Filter paper only
c) Distillation columns
d) Centrifugation - Purification of iodine is done by:
a) Sublimation
b) Filtration
c) Distillation
d) Chromatography
Types of Organic Reactions (18–24)
- CH₄ + Cl₂ → CH₃Cl + HCl is an example of:
a) Addition
b) Substitution
c) Elimination
d) Oxidation - H₂C=CH₂ + H₂ → CH₃–CH₃ is an example of:
a) Substitution
b) Addition
c) Elimination
d) Polymerization - C₂H₅OH → C₂H₄ + H₂O is an example of:
a) Oxidation
b) Reduction
c) Elimination
d) Substitution - Oxidation of ethanol to ethanal involves:
a) Addition
b) Substitution
c) Oxidation
d) Reduction - Bromination of ethene (C₂H₄) is an example of:
a) Substitution
b) Addition
c) Elimination
d) Redox - Combustion of methane is:
a) Redox reaction
b) Substitution only
c) Addition
d) Elimination - Esterification is an example of:
a) Addition
b) Substitution
c) Condensation reaction
d) Oxidation
Isomerism (25–31)
- Compounds with same molecular formula but different structures are called:
a) Isotopes
b) Isomers
c) Homologues
d) Allotropes - Structural isomers differ in:
a) Molecular formula
b) Functional group or connectivity
c) Physical state only
d) Molecular weight - Functional isomerism arises due to:
a) Different carbon chain
b) Different functional groups
c) Different isotopes
d) Different polarity - Geometrical isomerism occurs in:
a) Alkanes
b) Alkenes
c) Alkynes
d) Alcohols - Optical isomerism arises due to:
a) Presence of chiral carbon
b) Double bonds
c) Triple bonds
d) Functional group - Cis–trans isomerism is a type of:
a) Structural isomerism
b) Geometrical isomerism
c) Optical isomerism
d) Functional isomerism - Enantiomers are:
a) Non-superimposable mirror images
b) Same molecule
c) Structural isomers
d) Geometrical isomers
Nomenclature Basics (32–36)
- Prefix ‘methyl’ refers to:
a) –CH₃
b) –CH₂–
c) –CH
d) –C - The IUPAC name of CH₃–CH₂–OH is:
a) Methanol
b) Ethanol
c) Propanol
d) Ethanal - The parent chain is chosen based on:
a) Longest carbon chain
b) Shortest chain
c) Number of functional groups only
d) Number of hydrogens - Halogen substituents are named as:
a) Fluoro, Chloro, Bromo, Iodo
b) Hydro, Halo, Alkyl
c) Keto, Oxo
d) Alkyl - The functional group –COOH is named as:
a) Alcohol
b) Aldehyde
c) Carboxylic acid
d) Ketone
Conceptual & Application Questions (37–40)
- Organic compounds with same functional group and same general formula form:
a) Isotopes
b) Homologous series
c) Geometrical isomers
d) Optical isomers - Wurtz reaction is used to prepare:
a) Alkanes
b) Alkenes
c) Alkynes
d) Alcohols - Chromatography is mainly based on:
a) Boiling points
b) Adsorption and solubility
c) Density
d) Ionic character - Purification of naphthalene is done by:
a) Sublimation
b) Crystallization
c) Distillation
d) Filtration
Answer Key – Class 11 Chemistry: Organic Chemistry (40 MCQs)
Introduction to Organic Chemistry (1–4)
- b) Carbon – Organic chemistry primarily studies carbon compounds.
- b) CH₄ – Methane is an organic compound.
- b) Covalent – Organic compounds generally contain covalent bonds.
- b) Covalent bonds – Most common in organic molecules.
Methods of Preparation of Organic Compounds (5–10)
- c) Sabatier reaction – CH₄ is prepared by hydrogenation of CO or CO₂ on nickel catalyst.
- a) Fermentation of sugars – Ethanol is produced biologically.
- a) Halogenation – Alkyl halides are prepared by substitution of H with halogen.
- a) Wurtz reaction – Preparation of alkanes from alkyl halides.
- a) Cyclization – Acetylene is converted to benzene by trimerization (cyclization).
- a) Reaction of alkyl halide with Mg in dry ether – Standard Grignard reagent preparation.
Purification Techniques (11–17)
- c) Boiling points – Distillation separates based on volatility.
- b) <25°C – Fractional distillation is used for close boiling liquids.
- a) Solubility – Crystallization separates solids based on solubility differences.
- b) Organic solids that sublime – Sublimation purifies substances like iodine, camphor.
- b) Differential solubility and adsorption – Basis of paper chromatography.
- a) Glass plates coated with adsorbent – TLC technique.
- a) Sublimation – Purification of iodine and similar solids.
Types of Organic Reactions (18–24)
- b) Substitution – Methane reacts with Cl₂ via substitution.
- b) Addition – H₂ adds to ethene across double bond.
- c) Elimination – Ethanol loses water to form ethene.
- c) Oxidation – Ethanol oxidized to ethanal.
- b) Addition – Bromine adds to ethene double bond.
- a) Redox reaction – Combustion of methane involves oxidation-reduction.
- c) Condensation reaction – Ester formation involves condensation of acid and alcohol.
Isomerism (25–31)
- b) Isomers – Same molecular formula, different structures.
- b) Functional group or connectivity – Structural isomerism.
- b) Different functional groups – Functional isomerism arises due to functional group difference.
- b) Alkenes – Geometrical isomerism occurs due to restricted rotation around C=C.
- a) Presence of chiral carbon – Optical isomerism arises from chiral centers.
- b) Geometrical isomerism – Cis–trans is geometrical.
- a) Non-superimposable mirror images – Definition of enantiomers.
Nomenclature Basics (32–36)
- a) –CH₃ – Methyl group.
- b) Ethanol – CH₃–CH₂–OH.
- a) Longest carbon chain – Parent chain is longest chain with functional group priority.
- a) Fluoro, Chloro, Bromo, Iodo – Halogen substituents.
- c) Carboxylic acid – –COOH functional group.
Conceptual & Application Questions (37–40)
- b) Homologous series – Same functional group, general formula, successive members differ by –CH₂–.
- a) Alkanes – Wurtz reaction couples alkyl halides to form alkanes.
- b) Adsorption and solubility – Basis of chromatography separation.
- a) Sublimation – Purification of naphthalene exploits its ability to sublime.
Disclaimer:
All MCQs on this page are created for educational purposes only. They are intended for practice and NEET/Class 11 Chemistry preparation and do not guarantee any specific exam results.