Recent

  • Show all results for ""
Naming and Stability of Aromatic Compounds
37 Questions
0 Views

Naming and Stability of Aromatic Compounds

Created by
@IndulgentRetinalite2315

Questions and Answers

What is the correct naming convention for a monosubstituted benzene compound with the formula C6H5Br?

  • bromophenol
  • phenylbromide
  • bromobenzene (correct)
  • bromocyclohexane

    • Which description is true for a compound that is classified as a phenyl-substituted alkane?

  • It refers to a monosubstituted benzene.
  • The substituent is a phenyl group attached to a larger alkane. (correct)
  • It cannot have any additional substituents on the benzene ring.
  • It must contain fewer than six carbons in the substituent.

    • What is the prefix used to indicate a 1,2 substitution on a benzene ring?

  • para
  • di
  • meta
  • ortho (correct)

    • When naming disubstituted benzenes, which substitution pattern represents a 1,4 relationship?

    <p>para</p> Signup and view all the answers

    When naming a benzene compound, how should the substituents be listed?

    <p>Alphabetically.</p> Signup and view all the answers

    Which of the following statements about monosubstituted benzenes is incorrect?

    <p>Non-aromatic hydrocarbons can be named in the same way.</p> Signup and view all the answers

    What is the correct name for the C6H5CH2- group?

    <p>benzyl</p> Signup and view all the answers

    In a benzene ring with more than two substituents, what is the first step in determining the IUPAC name?

    <p>Assign numbers to the substituents ensuring the lowest numbers.</p> Signup and view all the answers

    What distinguishes benzene from the corresponding cycloalkane in terms of hydrogen atoms?

    <p>Benzene has six fewer hydrogens than cycloalkane.</p> Signup and view all the answers

    Comparing benzene to cyclohexene, what type of reaction does benzene undergo with bromine?

    <p>Substitution reaction</p> Signup and view all the answers

    What is the actual heat of hydrogenation, ΔH°hydrog, for benzene?

    <p>-206 kJ/mol</p> Signup and view all the answers

    How much more stable is benzene compared to the expected stability based on ΔH°hydrog?

    <p>150 kJ/mol</p> Signup and view all the answers

    What key characteristic defines the carbon-carbon bonds in benzene?

    <p>All bonds are identical in length.</p> Signup and view all the answers

    What is the shape and bond angle characteristic of benzene?

    <p>Planar with 120° bond angles.</p> Signup and view all the answers

    Which hybridization do all carbon atoms in benzene exhibit?

    <p>sp2-hybridized</p> Signup and view all the answers

    Why is it difficult to describe benzene using localized π bonds?

    <p>Each p orbital overlaps with all neighboring p orbitals.</p> Signup and view all the answers

    What is the significance of the Hückel rule in relation to polycyclic aromatic compounds?

    <p>It is only applicable to monocyclic compounds.</p> Signup and view all the answers

    Which of the following is a polycyclic aromatic compound that is associated with cancer-causing substances found in tobacco smoke?

    <p>Benzo[a]pyrene</p> Signup and view all the answers

    How many resonance forms does naphthalene have?

    <p>Three</p> Signup and view all the answers

    What is the aromatic stabilization energy of naphthalene measured during its heat of hydrogenation?

    <p>250 kJ/mol</p> Signup and view all the answers

    What kind of reaction does naphthalene predominantly undergo with electrophiles such as Br2?

    <p>Substitution products</p> Signup and view all the answers

    What must a molecule possess to be classified as aromatic according to Hückel's theory?

    <p>Planar, monocyclic, and 4n + 2 Π electrons</p> Signup and view all the answers

    Why are molecules with 4n Π electrons classified as antiaromatic?

    <p>Because delocalization leads to destabilization</p> Signup and view all the answers

    How many Π electrons does benzene contain that classify it as aromatic?

    <p>6</p> Signup and view all the answers

    Which of the following molecules is classified as antiaromatic?

    <p>Cyclobutadiene</p> Signup and view all the answers

    What structure does cyclooctatetraene adopt that prevents it from being aromatic?

    <p>Non-planar and tub-shaped</p> Signup and view all the answers

    Which of the following statements about aromatic ions is true?

    <p>They can contain different numbers of Π electrons and atoms in the ring</p> Signup and view all the answers

    What occurs when a saturated CH2 carbon in cyclopentadiene rehybridizes to sp2?

    <p>It results in full conjugation with a p orbital on every carbon</p> Signup and view all the answers

    How does a conjugated system relate to aromaticity based on Hückel's criteria?

    <p>It must involve p orbitals at each atom in a cyclic manner</p> Signup and view all the answers

    What type of product is formed when hydrogen is removed with both electrons from a C-H bond?

    <p>Carbocation</p> Signup and view all the answers

    Which ion is predicted to be aromatic according to Hückel’s rule?

    <p>Cycloheptatrienyl cation</p> Signup and view all the answers

    What is the pKa value of 1,3-cyclopentadiene, which indicates its acidity?

    <p>16</p> Signup and view all the answers

    Which of the following products is highly reactive and difficult to prepare?

    <p>Seven-p-electron cycloheptatrienyl radical</p> Signup and view all the answers

    How many π electrons does the cycloheptatrienyl cation possess?

    <p>6</p> Signup and view all the answers

    Which mechanism leads to the formation of a carbanion from a C-H bond?

    <p>Removing no electrons</p> Signup and view all the answers

    What distinguishes the cyclopentadienyl anion from other products formed from 1,3-cyclopentadiene?

    <p>It is remarkably stable.</p> Signup and view all the answers

    What kind of ion is formed when a hydride ion is removed from 1,3,5-cycloheptatriene?

    <p>Cycloheptatrienyl cation</p> Signup and view all the answers

    Study Notes

    Naming Aromatic Compounds

    • Monosubstituted benzenes use the suffix -benzene for systematic naming.
    • Alkyl groups smaller than six carbons lead to alkyl-substituted benzenes; larger groups result in phenyl-substituted alkanes.
    • Phenyl (Ph or ɸ) designates the C6H5 unit; benzyl refers to C6H5CH2-.
    • Disubstituted benzenes use prefixes: ortho (1,2), meta (1,3), para (1,4) for naming.
    • In compounds with multiple substituents, the lowest number for the second substituent is prioritized in the numbering.
    • Substituents in the compound's name are listed alphabetically.

    Stability and Structure of Benzene

    • Benzene (C6H6) has six fewer hydrogens than cyclohexane (C6H12) and is unsaturated with alternating bonds.
    • Benzene is less reactive than typical alkenes, undergoing substitution rather than addition reactions.
    • Stability can be quantitatively assessed via heats of hydrogenation; benzene releases less energy than expected, indicating greater stability.
    • All C-C bonds in benzene are of equal length (139 pm), intermediate between single and double bonds contributing to its stability.

    Aromaticity Criteria

    • According to Hückel’s rule, a compound must be cyclic, conjugated, and possess 4n + 2 π electrons to be considered aromatic.
    • Aromatic compounds have symmetrical electron density and a stable planar structure.
    • Non-aromatic compounds: Cyclobutadiene (4 π electrons, antiaromatic), Cyclooctatetraene (8 π electrons, non-aromatic).

    Aromatic Ions

    • Aromatic stability is not exclusive to neutral compounds; ions like the cyclopentadienyl anion and cycloheptatrienyl cation can also be aromatic.
    • Cyclopentadienyl anion is stable and can form easily; it showcases significant stability reflecting its aromatic nature.
    • Cycloheptatrienyl cation is extraordinarily stable, formed through the removal of specific hydrogen atoms from its corresponding hydrocarbons.

    Polycyclic Aromatic Compounds

    • Aromaticity is applicable to polycyclic compounds like naphthalene, anthracene, and benzo[a]pyrene, with multiple fused benzene rings.
    • These compounds demonstrate resonance stabilization, with naphthalene exhibiting aromatic stabilization energy of approximately 250 kJ/mol.
    • Reactivity patterns show substitution rather than addition, consistent with their aromatic nature.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    This quiz explores the systematic naming of aromatic compounds, including monosubstituted and disubstituted benzenes. It also delves into the stability and structure of benzene, comparing it with cyclohexane. Test your knowledge on the properties and nomenclature of these important organic compounds.

    More Quizzes Like This

    Benzene and Electrophilic Aromatic Substitution
    5 questions

    Benzene and Electrophilic Aromatic Substitution

    BeneficialWhale avatar
    BeneficialWhale
    Benzene and Aromatic Compounds Lecture Quiz
    15 questions

    Benzene Quiz: Test Your Knowledge of Aromatic Compounds

    ConciseCanto avatar
    ConciseCanto
    Aromatic Compounds: Properties, Reactions, and Applications
    12 questions

    Aromatic Compounds: Properties, Reactions, and Applications

    AngelicCosmos avatar
    AngelicCosmos
    Structure of Benzene
    40 questions

    Structure of Benzene

    SparklingLoyalty avatar
    SparklingLoyalty
    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser