Organic Chemistry Chapter 10: Carboxylic Acids and Derivatives
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Questions and Answers

What is the general formula for an aliphatic carboxylic acid?

  • RCO2H (correct)
  • RCHO
  • RCOOH
  • RCO3H

    • How are simple open-chain carboxylic acids named?

  • By adding the suffix –carboxylic acid to the parent alkane
  • By changing the infix -an- to -en-
  • By replacing the terminal –e of the alkane name with –oic acid (correct)
  • By replacing the terminal –e of the alkene name with –oic acid

    • What is the functional group of an acid halide?

  • An acyl group bonded to a halogen (correct)
  • A hydroxyl group bonded to a halogen
  • An alkyl group bonded to a halogen
  • A carboxyl group bonded to a halogen

    • How are acid anhydrides named?

    <p>By replacing the suffix -ic acid with -anhydride</p> Signup and view all the answers

    What is the functional group of an amide?

    <p>An acyl group bonded to a nitrogen atom</p> Signup and view all the answers

    Why are carboxylic acids more soluble in water than alcohols, ethers, aldehydes, and ketones of comparable molecular weight?

    <p>Due to their stronger intermolecular hydrogen bonds</p> Signup and view all the answers

    What is the range of pKa values for most aliphatic and aromatic carboxylic acids?

    <p>4-5</p> Signup and view all the answers

    Why do electron-withdrawing substituents near the carboxyl group increase acidity?

    <p>Due to their electron-withdrawing effect</p> Signup and view all the answers

    What is the most reactive type of carboxylic acid derivative towards nucleophilic acyl substitution?

    <p>Acid halide</p> Signup and view all the answers

    What is the mechanism of the Fischer esterification reaction of a carboxylic acid?

    <p>Nucleophilic acyl substitution</p> Signup and view all the answers

    What is the primary difference between hydrolysis of esters in aqueous acid and aqueous base?

    <p>The reversibility of the reaction</p> Signup and view all the answers

    What is the product of the reaction between an ester and a Grignard reagent?

    <p>A tertiary alcohol</p> Signup and view all the answers

    What is the role of the acid in the hydrolysis of esters in aqueous acid?

    <p>It is a catalyst</p> Signup and view all the answers

    What is the name of the process by which esters are hydrolyzed in basic solution?

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

    What is the reagent used to reduce esters to primary alcohols?

    <p>LiAlH4</p> Signup and view all the answers

    What is the primary reason why amides are less reactive than acid chlorides, acid anhydrides, and esters?

    <p>They are more stable</p> Signup and view all the answers

    What is the product of the reaction between an acid chloride and an amine?

    <p>An amide</p> Signup and view all the answers

    What is the reaction that converts amides into carboxylic acids?

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

    What is the primary reason why acid chlorides are preferred over acid anhydrides in chemical reactions?

    <p>Acid chlorides are more reactive</p> Signup and view all the answers

    What is the product of the reaction between an acid chloride and alcohol?

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

    What is the purpose of adding an extra equivalent of ammonia in the reaction between an acid chloride and ammonia?

    <p>To react with the HCl generated</p> Signup and view all the answers

    What is the intermediate reactant used in the conversion of carboxylic acids to amides?

    <p>Acid chloride</p> Signup and view all the answers

    What is the reaction between an acid chloride and water?

    <p>Substitution of –Cl by –OH</p> Signup and view all the answers

    Why are acid chlorides prepared from carboxylic acids using thionyl chloride?

    <p>To increase the reactivity of the acid</p> Signup and view all the answers

    What is the characteristic of simple esters?

    <p>Pleasant-smelling liquids</p> Signup and view all the answers

    What is the method used to prepare acid anhydrides?

    <p>Nucleophilic acyl substitution reaction</p> Signup and view all the answers

    What is the product of the reduction of amides by LiAlH4?

    <p>A primary amine</p> Signup and view all the answers

    What is the characteristic of the functional groups of nitriles and carboxylic acids?

    <p>They have a carbon atom with three bonds to an electronegative atom</p> Signup and view all the answers

    What is the mechanism of the reaction of cyanide ion with a primary alkyl halide to form a nitrile?

    <p>SN2 reaction</p> Signup and view all the answers

    What is the result of the hydrolysis of nitriles in either acidic or basic solution?

    <p>Formation of a carboxylic acid and ammonia</p> Signup and view all the answers

    What is the result of the reduction of nitriles with LiAlH4?

    <p>Formation of a primary amine</p> Signup and view all the answers

    What is the characteristic of the nitrile carbon atom?

    <p>It is electrophilic</p> Signup and view all the answers

    What is the primary function of lithium aluminum hydride (LiAlH4) in the conversion of carboxylic acids?

    <p>To reduce a carboxyl group to a 1° alcohol</p> Signup and view all the answers

    What is the main difference between the reduction of carboxylic acids by LiAlH4 and NaBH4?

    <p>LiAlH4 reduces carboxylic acids, while NaBH4 reduces aldehydes and ketones</p> Signup and view all the answers

    What is the purpose of using a catalyst like H2SO4 or gaseous HCl in the Fischer esterification reaction?

    <p>To increase the yield of the ester product</p> Signup and view all the answers

    What is the characteristic of the reduction of carboxylic acids by catalytic hydrogenation?

    <p>It is a highly non-selective reaction</p> Signup and view all the answers

    What is the reagent of choice for selectively reducing the carbonyl group of an aldehyde or ketone?

    <p>NaBH4</p> Signup and view all the answers

    What is the primary function of thionyl chloride in the conversion of carboxylic acids?

    <p>To convert a carboxyl group to an acid chloride</p> Signup and view all the answers

    What is the characteristic of the Fischer esterification reaction?

    <p>It is a reversible reaction that depends on the solvent</p> Signup and view all the answers

    What is the primary difference between the reduction of carboxylic acids by LiAlH4 and catalytic hydrogenation?

    <p>LiAlH4 reduces carboxylic acids, while catalytic hydrogenation reduces multiple functional groups</p> Signup and view all the answers

    Study Notes

    Naming Carboxylic Acids and Derivatives

    • Carboxylic acids are named by replacing the terminal -e of the alkane name with -oic acid
    • The -COOH carbon is always numbered C-1
    • If the compound contains a carbon-carbon double bond, change the infix -an- to -en-
    • Compounds with a -COOH group bonded to a ring are named using the suffix -carboxylic acid
    • The carboxyl group takes precedence over most other functional groups

    Functional Groups of Carboxylic Acids and Derivatives

    • Carboxylic acids: RCOOH (RCO2H)
    • Acid halides: RCOX (acyl group bonded to a halogen)
    • Acid anhydrides: RCOOCOR' (two acyl groups bonded to an oxygen atom)
    • Amides: RCONH2 (acyl group bonded to a nitrogen atom)
    • Esters: RCOOR' (acyl group bonded to -OR or -OAr)
    • Nitriles: R-C≡N (compounds containing the -C≡N functional group)

    Occurrence and Properties of Carboxylic Acids and Derivatives

    • In the liquid and solid states, carboxylic acids are associated by hydrogen bonding into dimeric structures
    • Carboxylic acids are polar compounds and form very strong intermolecular hydrogen bonds through both their C=O and OH groups
    • They are more soluble in water than alcohols, ethers, aldehydes, and ketones of comparable molecular weight
    • Water solubility decreases as the relative size of the hydrophobic portion of the molecule increases

    Acidity of Carboxylic Acids

    • Carboxylic acids are weak acids with pKa values ranging from 4 to 5
    • The greater acidity of carboxylic acids relative to alcohols is due to resonance stabilization of a carboxylate anion and the electron-withdrawing inductive effect of the adjacent carbonyl group
    • Electron-withdrawing substituents near the carboxyl group increase acidity through their inductive effect

    Synthesis of Carboxylic Acids

    • Oxidation of alkylbenzene (chapter 5)
    • Oxidation of primary alcohols and aldehydes
    • Prepared from nitriles, R-C≡N

    Nucleophilic Acyl Substitution Reactions

    • Carboxylic acid derivatives have an acyl carbon bonded to a group that can leave as a stable anion
    • The more electron-poor the C=O carbon, the more readily the compound reacts with nucleophiles
    • Halide ion is the weakest base and the best leaving group; acid halides are the most reactive toward nucleophilic acyl substitution

    Reactions of Carboxylic Acids

    • Conversion of acids into alcohols by reduction (RCOOH → RCH2OH)
    • Conversion of acids into acid chlorides (RCOOH → RCOCl)
    • Conversion of acids into esters (RCOOH → RCOOR')
    • Conversion of acids into amides (RCOOH → RCONH2)

    Chemistry of Acid Halides

    • Acid chlorides are prepared from carboxylic acids by reaction with thionyl chloride
    • Acid chlorides are among the most reactive of the various carboxylic acid derivatives and can be converted into many other kinds of substances

    Chemistry of Acid Anhydrides

    • The best method for preparing acid anhydrides is by a nucleophilic acyl substitution reaction of an acid chloride with a carboxylic acid anion
    • The reactions of acid anhydrides are similar to those of acid chlorides

    Chemistry of Esters

    • Many simple esters are pleasant-smelling liquids that are responsible for the fragrant odors of fruits and flowers
    • Esters are usually prepared from acids or acid chlorides
    • Conversion of esters into acids (RCOOR' → RCOOH)
    • Conversion of esters into alcohols by reduction (RCOOR' → RCH2OH)
    • Conversion of esters into alcohols by reaction with Grignard reagents (RCOOR' → RCH2OH)

    Chemistry of Amides

    • Amides are usually prepared by reaction of an acid chloride with an amine
    • Conversion of amides into acids (RCONH2 → RCOOH)
    • Conversion of amides into amines by reduction (RCONH2 → RCH2NH2)

    Chemistry of Nitriles

    • Nitriles are not acid derivatives, but the chemistries of nitriles are similar to carboxylic acids
    • The preparation of nitriles is by the SN2 reaction of cyanide ion with a primary alkyl halide
    • Conversion of nitriles into carboxylic acids (RCN → RCOOH)
    • Conversion of nitriles into amines by reduction (RCN → RCH2NH2)

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    Description

    This quiz covers the basics of carboxylic acids and derivatives, including their functional groups, naming conventions, and general formulas. It's a crucial chapter in organic chemistry.

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