Arrhenius

Definition

Arrhenius is a fundamental concept in chemistry, particularly in the context of acid-base titrations. It refers to the Swedish chemist Svante Arrhenius, who developed a theory to explain the behavior of acids and bases in aqueous solutions. The Arrhenius definition of an acid is a substance that increases the concentration of hydrogen ions (H+) when dissolved in water, while a base is a substance that increases the concentration of hydroxide ions (OH-) when dissolved in water. This understanding forms the basis for understanding the neutralization reactions that occur during acid-base titrations.

5 Must Know Facts For Your Next Test

1. The Arrhenius theory defines an acid as a substance that increases the concentration of hydrogen ions (H+) in an aqueous solution, and a base as a substance that increases the concentration of hydroxide ions (OH-) in an aqueous solution.
2. Arrhenius acids and bases undergo neutralization reactions, where the acidic and basic properties of the reactants are canceled out, resulting in the formation of a salt and water.
3. The pH scale, which ranges from 0 to 14, is used to measure the acidity or basicity of a solution based on the concentration of hydrogen ions (H+).
4. During an acid-base titration, the equivalence point is the point at which the amount of added titrant is exactly enough to neutralize the analyte, indicating the completion of the reaction.
5. The Arrhenius theory provides a fundamental understanding of the behavior of acids and bases in aqueous solutions, which is essential for interpreting and predicting the outcomes of acid-base titrations.

Review Questions

• Explain the Arrhenius definition of an acid and a base, and how they relate to the neutralization reactions that occur during acid-base titrations.
  • According to the Arrhenius theory, an acid is a substance that increases the concentration of hydrogen ions (H+) when dissolved in water, while a base is a substance that increases the concentration of hydroxide ions (OH-) when dissolved in water. During an acid-base titration, the neutralization reaction occurs when an acid and a base are combined, resulting in the formation of a salt and water. The Arrhenius definitions of acids and bases provide the foundation for understanding the behavior of these substances and the outcomes of the neutralization reactions that are observed during the titration process.
• Describe the role of pH in the context of Arrhenius acids and bases, and explain how it is used to determine the acidity or basicity of a solution during an acid-base titration.
  • The pH scale, which ranges from 0 to 14, is a measure of the acidity or basicity of a solution based on the concentration of hydrogen ions (H+). According to the Arrhenius theory, acids increase the concentration of H+ in an aqueous solution, resulting in a pH value less than 7, which is considered acidic. Conversely, bases increase the concentration of OH- in an aqueous solution, resulting in a pH value greater than 7, which is considered basic. During an acid-base titration, the pH of the solution changes as the titrant is added, and the equivalence point is reached when the pH is neutral (pH = 7), indicating that the acid and base have been completely neutralized.
• Analyze the significance of the equivalence point in an acid-base titration and explain how it is determined based on the Arrhenius theory of acids and bases.
  • The equivalence point in an acid-base titration is the point at which the amount of added titrant (the solution of known concentration) is exactly enough to neutralize the analyte (the solution of unknown concentration). This point is crucial because it indicates the completion of the neutralization reaction, where the acidic and basic properties of the reactants have been canceled out, resulting in the formation of a salt and water. The Arrhenius theory of acids and bases provides the foundation for understanding the behavior of these substances and the changes in pH that occur during the titration process. By monitoring the pH changes and identifying the equivalence point, the concentration of the unknown analyte can be determined, which is a key application of the Arrhenius theory in the context of acid-base titrations.

Related terms

pH:

pH is a measure of the acidity or basicity of a solution, based on the concentration of hydrogen ions (H+). It ranges from 0 to 14, with 7 being neutral, values less than 7 being acidic, and values greater than 7 being basic.

Neutralization Reaction: A neutralization reaction is a chemical reaction that occurs when an acid and a base are combined, resulting in the formation of a salt and water. The reaction is characterized by the cancellation of the acidic and basic properties of the reactants.

Equivalence Point:

The equivalence point in an acid-base titration is the point at which the amount of added titrant (the solution of known concentration) is exactly enough to neutralize the analyte (the solution of unknown concentration).