Functional Groups 3
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What is the result of heterolysis in a covalent bond?

  • Both electrons go to one fragment, forming ions. (correct)
  • The bond weakens, but no fragments are formed.
  • Both fragments retain their electrons.
  • A bond is formed between the two fragments.

    • Which characteristic defines a carbanion?

  • It contains exclusively σ bonds.
  • It has a positive charge.
  • It is a strong acid.
  • It possesses a lone pair of electrons. (correct)

    • How does a Bronsted-Lowry acid behave in a chemical reaction?

  • It accepts a proton.
  • It donates an electron pair.
  • It donates a proton. (correct)
  • It remains neutral without participating.

    • Which of these is a characteristic of electrophiles?

    <p>They are electron pair acceptors.</p> Signup and view all the answers

    What type of bond-breaking process results in the formation of carbocations?

    <p>Heterolysis of a polar bond.</p> Signup and view all the answers

    Which factor does NOT affect the strength of acids?

    <p>The number of hydrogen atoms present in the molecule.</p> Signup and view all the answers

    What type of reaction occurs when bromine reacts with ethene?

    <p>Addition reaction.</p> Signup and view all the answers

    Which type of bond-breaking generates free radicals?

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

    Which of the following statements about pKa values is true?

    <p>A lower pKa emphasizes a stronger acid.</p> Signup and view all the answers

    What primarily influences the strength of an acid?

    <p>The ability of the anion to delocalize the negative charge.</p> Signup and view all the answers

    Which of the following correctly describes a Bronsted-Lowry acid?

    <p>A substance that donates a proton.</p> Signup and view all the answers

    Which factor contributes to ammonia acting as a base in water?

    <p>It has an unbonded electron pair that can bond with a proton.</p> Signup and view all the answers

    What is the approximate ionization for a compound when pH is equal to pKa + 2?

    <p>99% ionized.</p> Signup and view all the answers

    Which of the following statements is true about carboxylic acids?

    <p>They can dissociate to donate a proton due to their acidic hydrogen.</p> Signup and view all the answers

    Which compound is likely to be a stronger base based on conjugate acid pKa?

    <p>A compound with a conjugate acid pKa of 15.</p> Signup and view all the answers

    What characteristic of a carbanion contributes to its stability?

    <p>The ability to resonance stabilize the negative charge.</p> Signup and view all the answers

    What term describes a species that seeks an electron pair due to having a positive charge?

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

    Which of the following best describes a carbanion?

    <p>A species with six electrons in its valence shell</p> Signup and view all the answers

    In the Bronsted-Lowry definition, how is an acid defined?

    <p>A substance that donates a proton</p> Signup and view all the answers

    What is the relationship between the equilibrium constant Ka and the strength of an acid?

    <p>A lower Ka indicates a weaker acid</p> Signup and view all the answers

    Which term is used to refer to a species that donates an electron pair in a reaction?

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

    What happens to a strong acid in an aqueous solution in terms of ionization?

    <p>It ionizes completely</p> Signup and view all the answers

    What is produced as a result of homolytic cleavage of a bond?

    <p>Free radicals</p> Signup and view all the answers

    Which of the following statements about carbocations is true?

    <p>They seek electron pairs to achieve stability</p> Signup and view all the answers

    What type of reaction is exemplified when the OH group replaces a Cl atom in an organic molecule?

    <p>This reaction is a substitution reaction.</p> Signup and view all the answers

    Identify the key feature of addition reactions in organic chemistry.

    <p>Addition reactions involve the combination of two molecules to form a single product.</p> Signup and view all the answers

    What process occurs during an elimination reaction?

    <p>In an elimination reaction, elements from a molecule are removed, often resulting in the formation of a double bond.</p> Signup and view all the answers

    Describe the difference between heterolytic and homolytic cleavage.

    <p>Heterolytic cleavage involves both electrons going to one fragment, while homolytic cleavage results in each fragment receiving one electron.</p> Signup and view all the answers

    What type of ion is formed as a result of heterolysis?

    <p>Heterolysis produces ions, specifically a carbocation or a carbanion.</p> Signup and view all the answers

    What type of bond breaking produces free radicals?

    <p>Homolytic cleavage generates free radicals.</p> Signup and view all the answers

    What do you understand by the term 'substitutions' in organic reactions?

    <p>Substitutions refer to reactions where one atom or group is replaced by another in a compound.</p> Signup and view all the answers

    What defines a carbocation in terms of structure?

    <p>A carbocation is defined as a positively charged carbon atom with only six valence electrons.</p> Signup and view all the answers

    What is the role of a carbocation in chemical reactions?

    <p>A carbocation acts as an electrophile, seeking electron pairs to stabilize its positive charge.</p> Signup and view all the answers

    How does a Lewis acid differ from a Bronsted-Lowry acid?

    <p>A Lewis acid is an electron pair acceptor, while a Bronsted-Lowry acid donates a proton (H+).</p> Signup and view all the answers

    What distinguishes a nucleophile from an electrophile?

    <p>A nucleophile is a species that seeks out positive charges and donates an electron pair, whereas an electrophile accepts electron pairs.</p> Signup and view all the answers

    What is the outcome of homolytic cleavage of a bond?

    <p>Homolytic cleavage results in the formation of two free radicals, with each atom retaining one of the shared electrons.</p> Signup and view all the answers

    Why are carbanions considered reactive species?

    <p>Carbanions are reactive because they possess a negative charge and can donate an electron pair to stabilize themselves.</p> Signup and view all the answers

    What happens to the equilibrium constant Ka when the equilibrium lies to the left?

    <p>When the equilibrium lies to the left, the value of Ka is small, indicating that the acid does not readily ionize.</p> Signup and view all the answers

    What characterizes a substance as a Lewis base?

    <p>A Lewis base is characterized as an electron pair donor in a chemical reaction.</p> Signup and view all the answers

    How does the presence of an electron pair affect the reactivity of a nucleophile?

    <p>The presence of an electron pair enhances the nucleophile's ability to interact with electrophiles and stabilize their positive charge.</p> Signup and view all the answers

    What does a low pKa value indicate about an acid's strength?

    <p>A low pKa value indicates that the acid is stronger.</p> Signup and view all the answers

    Why is ethanoic acid a stronger acid than ethanol?

    <p>Ethanoic acid is stronger due to the resonance stabilization of its anion after losing a proton.</p> Signup and view all the answers

    What is the general formula for carboxylic acids?

    <p>The general formula for carboxylic acids is RCOOH or RCO2H.</p> Signup and view all the answers

    How does pH relate to pKa in determining ionization of weak acids?

    <p>When pH = pKa, the compound is approximately 50% ionized.</p> Signup and view all the answers

    What role does the presence of a proton play in acidic functional groups?

    <p>The presence of a proton allows the group to donate it, contributing to its acidic properties.</p> Signup and view all the answers

    What does it mean for a base if its conjugate acid has a larger pKa?

    <p>A larger pKa of the conjugate acid indicates a stronger base.</p> Signup and view all the answers

    Explain what characteristics contribute to the strength of weak acids.

    <p>The strength of weak acids is influenced by their pKa value and the stability of the resulting anion.</p> Signup and view all the answers

    What is a key feature of bases in the context of proton acceptance?

    <p>A base must have an unbonded electron pair available to bond with a proton.</p> Signup and view all the answers

    Study Notes

    Organic Functional Groups

    • Organic reactions are categorized into substitutions, additions, or eliminations.
    • Substitution reactions involve replacing one atom or group with another. An example shows the OH group substituting the Cl atom in a molecule, producing an alcohol. This type of reaction is common in saturated molecules.

    Addition Reactions

    • Addition reactions occur with compounds containing multiple π bonds.
    • The reaction of ethene with bromine is an example. This results in a single molecule formed from two individual molecules.

    Elimination Reactions

    • These are the opposite of addition reactions.
    • In elimination reactions, a molecule loses components of another small molecule, often creating multiple bonded products.
    • To understand these reactions, bond-breaking processes must be understood.

    Bond Breaking Processes

    • Heterolysis: Both electrons in the covalent bond move to one fragment, producing ions. This occurs in polar bonds.

      • A-B → A+ + B-

    • Homolysis: Each electron in the covalent bond goes to a different fragment, forming free radicals.

      • A-B → A• + B•

    Carbocations and Carbanions

    • When bonds involve carbon, carbocations or carbanions can be formed.
    • Carbocation formation involves moving electrons to create a positive carbon center.
    • Carbanions are created by moving electrons to create a negative carbon center.
    • Carbocations and carbanions are highly reactive.

    Electrophiles and Nucleophiles

    • Electrophiles seek electrons to achieve a stable valence shell.
    • Nucleophiles seek out positive centers and have an unbonded electron pair.
    • Acids are electron pair acceptors.
    • Bases are electron pair donors.

    Acids

    • Organic acids generally do not readily dissociate to lose H+ ions to water.
    • pKa values are used to determine the strength of an acid.
    • Lowering the pKa value means the acid is stronger.
    • The strength of an acid depends on the stability of the anion formed after losing H+.

    Bases

    • Bases accept protons from other molecules.
    • Base strength is measured using the pKa values of the conjugate acids formed.
    • Higher pKa values indicate a stronger base.

    Functional Groups

    • These groups determine the properties and reactivity of a molecule.
    • Acidic functional groups can donate or lose a proton.
      • This requires a dissociable hydrogen atom (proton).
      • The remaining atoms must be able to delocalize the resulting negative charge.
    • Basic functional groups can accept a proton.
      • This requires an unbonded electron pair that can bond to and accept the proton.

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    Organic Functional Groups Lecture 3 PDF

    Description

    Test your knowledge on organic functional groups and reactions, including substitution, addition, and elimination processes. This quiz also covers bond-breaking mechanisms such as heterolysis. Challenge yourself to understand the core concepts of organic chemistry!

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