3.3.9.1 Acidity of Carboxylic Acids

• Carboxylic acids have a carboxyl group (-COOH) as their functional group.


  True
• The acid dissociation constant (Ka) quantifies the ability of an acid to release protons in water.


  True
• Order the factors influencing carboxylic acid acidity based on their effect:

  1️⃣ Inductive Effect

  2️⃣ Resonance Stabilization

  3️⃣ Steric Effects
• Why is trifluoroacetic acid (CF3COOH) more acidic than acetic acid (CH3COOH)?

  Electron-withdrawing effect
• Acetic acid is less acidic than trifluoroacetic acid due to the electron-withdrawing effect of the fluorine atoms.


  True
• Match the example with its functional group:

  Acetic acid ↔️ Carboxyl (-COOH)

  Phenol ↔️ Hydroxyl (-OH)

  Methylamine ↔️ Amino (-NH2)
• What is the Ka value of acetic acid?

  1.8 × 10^-5
• Match the structural component with its description:

  Carboxyl group ↔️ -COOH

  Carbonyl group ↔️ C=O

  Hydroxyl group ↔️ -OH
• Match the term with its definition:

  Acid strength ↔️ Ability to release protons

  Ka value ↔️ Quantifies acid strength

  Resonance ↔️ Stabilizes carboxylate ion
• Resonance stabilization increases the acidity of carboxylic acids, particularly in aromatic
• Phenols are stronger acids than carboxylic acids.

  False
• Electron-withdrawing substituents enhance acidity by stabilizing the negative charge on the conjugate base
• The inductive effect enhances acidity by stabilizing the negative charge on the conjugate base
• In carboxylic acids, resonance stabilization occurs within the carboxyl
• The carboxyl group (-COOH) in carboxylic acids consists of a carbonyl group (C=O) and a hydroxyl
• What is the primary reason for the acidity of carboxylic acids?

  Proton release
• What is the chemical equation for the dissociation of a carboxylic acid?

  R-COOH (aq) ⇌ R-COO- (aq) + H+ (aq)</latex>
• The carboxylate ion is stabilized by resonance in the carboxyl group, which increases its acidity
• Bulky substituents near the carboxyl group can decrease acidity by hindering proton release and carboxylate ion formation
• The carboxylate ion in carboxylic acids is stabilized by resonance, which enhances acidity.

  True
• Electron-withdrawing substituents enhance acidity by stabilizing the negative charge on the conjugate base
• Amines are basic due to the lone pair of electrons on the nitrogen atom, which can accept protons.


  True
• Alcohols are neutral, while carboxylic acids are acidic
• Order the following substituents based on their effect on acidity, from most increasing to most decreasing:

  1️⃣ Electron-withdrawing groups

  2️⃣ Resonance stabilization

  3️⃣ Electron-donating groups
• Carboxylate ions are stabilized by resonance
• Resonance stabilization increases the acidity of carboxylate ions.


  True
• Resonance stabilization is significant in amines.

  False
• Resonance stabilization in the carboxylate ion shifts the equilibrium towards the products.

  True
• Benzoic acid is more acidic than acetic acid due to greater resonance stabilization.


  True
• Electron-donating groups decrease the acidity of carboxylic acids.

  True
• Electron-withdrawing groups in carboxylic acids stabilize the carboxylate ion by dispersing its negative charge
• What is the general structure of carboxylic acids?

  R-COOH
• What is the acid dissociation constant (Ka) used for?

  Measuring acid strength
• Why is trifluoroacetic acid more acidic than acetic acid?

  Fluorine is electron-withdrawing
• Why is benzoic acid more acidic than acetic acid?

  Resonance with aromatic ring
• How does resonance stabilization enhance the acidity of carboxylic acids?

  Lowers energy for dissociation
• Through which type of bonds does resonance occur?

  Pi bonds
• What type of group does acetic acid have, and how does it affect its acidity?

  Alkyl group, lowers acidity
• Electron-donating groups in carboxylic acids hinder proton release

  True
• The acidic nature of carboxylic acids allows them to be used in various applications, from food preservation to industrial and pharmaceutical uses