- Which of the following is the general formula of cycloalkanes?
a) CnH2n+2
b) CnH2n
c) CnH2n-2
d) CnHn
Answer: b) CnH2n - What is the first member of the cycloalkane series?
a) Cyclobutane
b) Cyclopropane
c) Cyclopentane
d) Cyclohexane
Answer: b) Cyclopropane - Cycloalkanes are also known as:
a) Aromatic compounds
b) Cycloparaffins
c) Cycloalkenes
d) Alkynes
Answer: b) Cycloparaffins - Cycloalkanes are functionally isomeric with which of the following?
a) Alkynes
b) Alkenes
c) Alkanes
d) Alcohols
Answer: b) Alkenes - What prefix is used while naming simple cycloalkanes?
a) Iso-
b) Cyclo-
c) Neo-
d) Sec-
Answer: b) Cyclo- - What is the molecular formula of cyclobutane?
a) C4H8
b) C4H10
c) C3H6
d) C5H10
Answer: a) C4H8 - Which statement is correct about bicyclo[2.2.1]heptane?
a) It has 7 carbon atoms in the main chain
b) It has 3 rings
c) It has 2 bridgehead carbons and 3 bridges
d) It is aromatic
Answer: c) It has 2 bridgehead carbons and 3 bridges - Which method uses dihalogen compounds to prepare cycloalkanes?
a) Clemmensen reduction
b) Wurtz reaction
c) Dieckmann condensation
d) Friedel–Crafts reaction
Answer: b) Wurtz reaction - Which reagent is used in the Clemmensen reduction?
a) Zn(Hg)/HCl
b) NaBH4
c) LiAlH4
d) KMnO4
Answer: a) Zn(Hg)/HCl - Hydrogenation of benzene gives which cycloalkane?
a) Cyclopentane
b) Cyclopropane
c) Cyclohexane
d) Cyclobutane
Answer: c) Cyclohexane - Which reaction involves intramolecular acetoacetic ester condensation?
a) Cannizzaro reaction
b) Dieckmann reaction
c) Friedel-Crafts reaction
d) Aldol condensation
Answer: b) Dieckmann reaction - Cycloalkanes mostly show reactions similar to:
a) Aromatic compounds
b) Alkanes
c) Alkenes
d) Alcohols
Answer: b) Alkanes - Which reagent causes halogenation of cycloalkanes?
a) Halogen + UV light
b) Conc. HCl
c) Dilute KMnO4
d) Sulphuric acid
Answer: a) Halogen + UV light - What happens when cyclopropane reacts with Cl₂ in dark?
a) Addition without ring opening
b) Substitution
c) Ring opening to 1,3-dichloropropane
d) Oxidation
Answer: c) Ring opening to 1,3-dichloropropane - Which catalyst is used for hydrogenation of cyclopropane?
a) Nickel
b) Platinum
c) Iron
d) Zinc
Answer: a) Nickel - Which cycloalkanes readily undergo catalytic hydrogenation?
a) Cyclopentane and higher
b) Only cyclopropane and cyclobutane
c) All cycloalkanes
d) None
Answer: b) Only cyclopropane and cyclobutane - Who proposed the Baeyer strain theory?
a) Adolf von Baeyer
b) August Kekulé
c) Robert Robinson
d) Friedrich Wöhler
Answer: a) Adolf von Baeyer - According to Baeyer strain theory, what causes instability in cycloalkanes?
a) Presence of double bonds
b) Angle strain
c) Steric hindrance
d) Resonance
Answer: b) Angle strain - Which has the maximum angle strain according to Baeyer?
a) Cyclopentane
b) Cyclohexane
c) Cyclopropane
d) Cyclobutane
Answer: c) Cyclopropane - According to Baeyer, which is the most stable?
a) Cyclopropane
b) Cyclopentane
c) Cyclohexane
d) Cyclobutane
Answer: b) Cyclopentane - What is the major drawback of Baeyer’s strain theory?
a) Assumes all rings are planar
b) Assumes rings are aromatic
c) Does not apply to cyclopropane
d) Cannot explain alkene stability
Answer: a) Assumes all rings are planar - Which shape of Cyclohexane is predicted by Sachse-Mohr theory?
a) Linear
b) Square planar
c) Chair and boat
d) Octahedral
Answer: c) Chair and boat - According to Sachse-Mohr, cyclohexane is stable because:
a) It is planar
b) It has π-bonds
c) It has no angle strain in non-planar forms
d) It has bent bonds
Answer: c) It has no angle strain in non-planar forms - Coulson and Moffitt proposed which concept for Cyclopropane?
a) Resonance
b) Bent (banana) bonds
c) Pi bonds
d) Hydrogen bonding
Answer: b) Bent (banana) bonds - Bent bonds are:
a) Pure sigma bonds
b) Pure pi bonds
c) Intermediate between sigma and pi bonds
d) Ionic bonds
Answer: c) Intermediate between sigma and pi bonds - Which of the following has the formula C5H10 and is a cycloalkane?
a) Pentane
b) Cyclopentane
c) Pentene
d) Pentadiene
Answer: b) Cyclopentane - How many hydrogen atoms are in Cyclohexane?
a) 10
b) 12
c) 14
d) 16
Answer: b) 12 - 1,3-dibromopropane on treatment with sodium gives:
a) Cyclobutane
b) Cyclopropane
c) Propene
d) Propane
Answer: b) Cyclopropane - Calcium adipate on dry distillation gives:
a) Cyclobutane
b) Cyclopentane
c) Cyclopentanone
d) Cyclohexane
Answer: c) Cyclopentanone - Which reaction converts cyclohexanone to cyclohexane?
a) Clemmensen reduction
b) Aldol condensation
c) Kolbe reaction
d) Birch reduction
Answer: a) Clemmensen reduction - Dieckmann condensation involves:
a) Intermolecular ester condensation
b) Intramolecular ester condensation
c) Ketone oxidation
d) Alcohol dehydration
Answer: b) Intramolecular ester condensation - Catalytic hydrogenation of Benzene gives:
a) Cyclobutane
b) Cyclohexane
c) Cyclopentane
d) Cycloheptane
Answer: b) Cyclohexane - Which of the following requires UV light?
a) Bromination of cycloalkanes
b) Hydrogenation
c) Halogen addition
d) Nitration
Answer: a) Bromination of cycloalkanes - Cyclopropane reacts with Cl₂ in dark to form:
a) 1,2-dichloropropane
b) 1,3-dichloropropane
c) 1,3,5-trichloropropane
d) Chlorocyclopropane
Answer: b) 1,3-dichloropropane - Reaction of cyclopropane with HI gives:
a) 1-iodopropane
b) 2-iodopropane
c) 3-iodopropane
d) Iodocyclopropane
Answer: a) 1-iodopropane - Which cycloalkane is inert towards catalytic hydrogenation?
a) Cyclopropane
b) Cyclobutane
c) Cyclopentane
d) Cyclohexane
Answer: c) Cyclopentane - What is formed when cyclobutane is catalytically hydrogenated?
a) n-Butane
b) Butene
c) Propane
d) Methane
Answer: a) n-Butane - Normal tetrahedral bond angle is:
a) 90°
b) 120°
c) 109.5°
d) 180°
Answer: c) 109.5° - C–C–C angle in Cyclopropane is:
a) 90°
b) 60°
c) 120°
d) 109.5°
Answer: b) 60° - Angle strain in cyclopropane is:
a) 9°44′
b) 5°16′
c) 24°44′
d) 0°
Answer: c) 24°44′ - C–C–C angle in Cyclobutane is:
a) 109.5°
b) 120°
c) 60°
d) 90°
Answer: d) 90° - Angle strain in cyclobutane is:
a) 24°44′
b) 9°44′
c) 0°44′
d) 12°46′
Answer: b) 9°44′ - C–C–C angle in Cyclopentane is:
a) 108°
b) 120°
c) 109.5°
d) 90°
Answer: a) 108° - Angle strain in cyclopentane is:
a) 9°44′
b) 24°44′
c) 0°44′
d) 12°46′
Answer: c) 0°44′ - C–C–C angle in Cyclohexane is (planar assumption):
a) 120°
b) 109.5°
c) 90°
d) 108°
Answer: a) 120° - Angle strain in cyclohexane is:
a) 12°46′
b) −5°16′
c) 0°44′
d) 24°44′
Answer: b) −5°16′ - Which cycloalkane is most unstable according to Baeyer?
a) Cyclopentane
b) Cyclobutane
c) Cyclopropane
d) Cyclohexane
Answer: c) Cyclopropane - Baeyer assumed all rings are:
a) Non-planar
b) Aromatic
c) Planar
d) Bent
Answer: c) Planar - Which fact contradicts Baeyer’s theory?
a) Cyclohexane is more stable than cyclopentane
b) Cyclopropane is unstable
c) Cyclopentane is stable
d) Angle strain causes instability
Answer: a) Cyclohexane is more stable than cyclopentane - Why are larger ring systems stable?
a) They are aromatic
b) They are planar
c) They are puckered, reducing strain
d) They are alkenes
Answer: c) They are puckered, reducing strain - Who proposed Sachse-Mohr theory?
a) Ernst Sachse and Walter Mohr
b) Robert Robinson
c) Linus Pauling
d) Friedrich Kekulé
Answer: a) Ernst Sachse and Walter Mohr - Sachse-Mohr theory explains:
a) Planarity of rings
b) Strainless rings
c) Aromaticity
d) Hyperconjugation
Answer: b) Strainless rings - Cyclohexane exists in:
a) Chair and boat conformations
b) Planar conformation
c) Tetrahedral conformation
d) Octahedral conformation
Answer: a) Chair and boat conformations - Which is the more stable form of cyclohexane?
a) Boat
b) Chair
c) Planar
d) Sawhorse
Answer: b) Chair - Why is boat form less stable?
a) Angle strain
b) Steric repulsion between flagpole hydrogens
c) Resonance
d) Planarity
Answer: b) Steric repulsion between flagpole hydrogens - Interconversion of chair forms occurs through:
a) Bond breaking
b) Rotation around C–C bonds
c) Hydrogen bonding
d) Ionic rearrangement
Answer: b) Rotation around C–C bonds - How many hydrogen atoms are axial in chair form of cyclohexane?
a) 3
b) 6
c) 12
d) 4
Answer: b) 6 - Coulson-Moffitt explained bonding in:
a) Cyclopentane
b) Cyclopropane
c) Cyclohexane
d) Cyclobutane
Answer: b) Cyclopropane - Bent bonds are also called:
a) Sigma bonds
b) Banana bonds
c) Pi bonds
d) Ionic bonds
Answer: b) Banana bonds - Bent bonds are:
a) More stable than sigma bonds
b) Less stable than sigma but more stable than pi
c) Same as pi bonds
d) Ionic
Answer: b) Less stable than sigma but more stable than pi - Why are bent bonds formed?
a) To reduce angle strain
b) To increase resonance
c) To decrease resonance
d) To increase aromaticity
Answer: a) To reduce angle strain - Cycloalkanes are classified as:
a) Aromatic
b) Alicyclic
c) Alkenes
d) Aromatic heterocycles
Answer: b) Alicyclic - Number of σ bonds in Cyclobutane:
a) 8
b) 10
c) 12
d) 14
Answer: c) 12 - Hybridisation of carbon in cycloalkanes:
a) sp
b) sp²
c) sp³
d) sp³d
Answer: c) sp³ - Which cycloalkane has the least ring strain?
a) Cyclopentane
b) Cyclobutane
c) Cyclopropane
d) Cyclohexane
Answer: d) Cyclohexane - Which one is a saturated hydrocarbon?
a) Cyclohexane
b) Benzene
c) Cyclohexene
d) Cycloheptene
Answer: a) Cyclohexane - The formula of cycloheptane is:
a) C7H16
b) C7H12
c) C7H14
d) C7H10
Answer: c) C7H14 - Deviation angle for Cycloheptane is:
a) +9°44′
b) −9°33′
c) −12°46′
d) +24°44′
Answer: b) −9°33′ - Deviation angle for Cyclooctane is:
a) −12°46′
b) +12°46′
c) −9°33′
d) 0°44′
Answer: a) −12°46′ - Sign (+) in Baeyer strain table means:
a) Bonds are expanded
b) Bonds are compressed
c) Bonds are aromatic
d) Bonds are planar
Answer: b) Bonds are compressed - Sign (−) in Baeyer strain table means:
a) Bonds are compressed
b) Bonds are bent
c) Bonds are widened
d) Bonds are broken
Answer: c) Bonds are widened - Which ring has nearly zero angle strain according to Baeyer?
a) Cyclopentane
b) Cyclohexane
c) Cycloheptane
d) Cyclobutane
Answer: a) Cyclopentane - In chair form of Cyclohexane, each carbon atom has how many axial hydrogens?
a) 2
b) 1
c) 3
d) 0
Answer: b) 1 - In chair form of cyclohexane, total number of equatorial hydrogens are:
a) 3
b) 4
c) 6
d) 8
Answer: c) 6 - Boat conformation is less stable due to:
a) Hyperconjugation
b) Angle strain
c) Flagpole interaction
d) Resonance
Answer: c) Flagpole interaction - Chair-chair interconversion of cyclohexane is also called:
a) Ring flipping
b) Bond shifting
c) Bond rotation
d) Chain inversion
Answer: a) Ring flipping - During ring flip, axial hydrogens become:
a) Planar
b) Equatorial
c) Aromatic
d) Ionic
Answer: b) Equatorial - Reaction of cycloalkane with halogen in UV light is:
a) Substitution
b) Addition
c) Elimination
d) Rearrangement
Answer: a) Substitution - Reaction of Cyclopropane with Cl₂ in dark is:
a) Substitution
b) Addition with ring opening
c) Oxidation
d) Polymerisation
Answer: b) Addition with ring opening - Which of these does not break the ring?
a) Cl₂ in dark
b) HI
c) UV light halogenation
d) HBr
Answer: c) UV light halogenation - Which cycloalkanes break to form straight-chain alkanes on hydrogenation?
a) Cyclopentane and cyclohexane
b) Cyclopropane and cyclobutane
c) Cycloheptane and cyclooctane
d) All cycloalkanes
Answer: b) Cyclopropane and cyclobutane - Cyclopropane + H₂/Ni gives:
a) n-Propane
b) Cyclopropanol
c) Propene
d) Allyl chloride
Answer: a) n-Propane - Sachse-Mohr theory explains stability of:
a) Small rings only
b) Medium and larger rings
c) Aromatic compounds
d) Alkenes
Answer: b) Medium and larger rings - Why are cyclohexane rings not planar?
a) Planarity increases angle strain
b) Planarity increases polarity
c) Planarity increases aromaticity
d) Planarity decreases resonance
Answer: a) Planarity increases angle strain - According to Sachse, each C atom retains:
a) Planar angle 120°
b) Tetrahedral angle 109.5°
c) Bent angle 60°
d) Linear angle 180°
Answer: b) Tetrahedral angle 109.5° - Non-planar forms remove which type of strain?
a) Angle strain
b) Resonance strain
c) Hyperconjugation
d) Aromatic strain
Answer: a) Angle strain - Coulson-Moffitt modification was introduced to explain:
a) Chair form of cyclohexane
b) Banana bonds in cyclopropane
c) Resonance in benzene
d) Sigma bonds in methane
Answer: b) Banana bonds in cyclopropane - Bent bonds are directed:
a) Straight along bond axis
b) Slightly outward away from bond axis
c) Perpendicular to bond axis
d) Below the molecular plane
Answer: b) Slightly outward away from bond axis - Bent bonds relieve:
a) Torsional strain
b) Angle strain
c) Van der Waals strain
d) Resonance strain
Answer: b) Angle strain - Hybrid orbitals in bent bonds are:
a) Pure p
b) sp²
c) sp³ but bent
d) sp
Answer: c) sp³ but bent - Bent bonds make Cyclopropane:
a) Less reactive than alkanes
b) Slightly more stable than predicted by Baeyer
c) Aromatic
d) Nonpolar
Answer: b) Slightly more stable than predicted by Baeyer
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