Propanoic Acid

Definition

Propanoic acid, also known as propionic acid, is a carboxylic acid with the chemical formula CH3CH2COOH. It is a colorless liquid with a pungent odor and is widely used in various industries and applications.

5 Must Know Facts For Your Next Test

1. Propanoic acid is a member of the homologous series of carboxylic acids, with the general formula CnH2n+1COOH.
2. It is a weak acid, with a pKa value of 4.87, meaning it partially dissociates in water to form hydrogen ions (H+) and propanoate ions (CH3CH2COO-).
3. Propanoic acid is used as a preservative in food, animal feed, and pharmaceuticals due to its antimicrobial properties.
4. It is also used in the production of various esters, which are used as solvents, fragrances, and plasticizers.
5. Propanoic acid can be synthesized through the oxidation of propanol or the carbonylation of ethylene.

Review Questions

• Explain the structure and properties of propanoic acid as a carboxylic acid.
  • Propanoic acid is a carboxylic acid with the chemical formula CH$_3$CH$_2$COOH. The carboxyl group (-COOH) consists of a carbonyl group (C=O) and a hydroxyl group (-OH), which gives propanoic acid its acidic properties. As a member of the homologous series of carboxylic acids, propanoic acid has a linear carbon chain with three carbon atoms and a carboxyl group at the end. This structure contributes to its physical and chemical properties, such as its pungent odor, partial dissociation in water, and use as a preservative and in the production of various esters.
• Describe the role of propanoic acid in the context of carboxylic acid structure and properties.
  • Propanoic acid is an important example of a carboxylic acid that demonstrates key structural and property features of this functional group. As a three-carbon carboxylic acid, propanoic acid illustrates the general formula and homologous series of carboxylic acids, where the carbon chain length varies. The presence of the carboxyl group (-COOH) gives propanoic acid its characteristic acidity, as the hydrogen atom can dissociate to form a proton (H$^+$) and a propanoate ion (CH$_3$CH$_2$COO$^-$). This acid-base behavior is crucial for understanding the reactivity and applications of carboxylic acids like propanoic acid in various chemical processes and industries.
• Analyze the significance of propanoic acid's structure and properties in the context of 20.2 Structure and Properties of Carboxylic Acids.
  • Propanoic acid is an excellent model for understanding the key structural features and properties of carboxylic acids covered in section 20.2. Its three-carbon linear chain and terminal carboxyl group (-COOH) exemplify the general structure of this functional group, which is critical for their characteristic acidity and reactivity. The partial dissociation of propanoic acid in water to form hydrogen ions (H$^+$) and propanoate ions (CH$_3$CH$_2$COO$^-$) demonstrates the acid-base behavior that is central to the chemistry of carboxylic acids. Furthermore, propanoic acid's use as a preservative and in the production of esters highlights the practical applications of carboxylic acids based on their structure and properties, such as their ability to form hydrogen bonds and undergo various reactions. Analyzing propanoic acid in this context provides a comprehensive understanding of the fundamental concepts covered in section 20.2.

Related terms

Carboxylic Acid: Carboxylic acids are organic compounds that contain a carboxyl group (-COOH), which consists of a carbonyl group (C=O) and a hydroxyl group (-OH).

Homologous Series: A homologous series is a series of organic compounds that differ by a repeating unit, such as a methylene group (-CH2-), and have similar chemical properties.

Acidity: Acidity refers to the ability of a substance to donate protons (H+) or accept electrons, which determines its pH and reactivity.