Introduction to Titration

Chapter: Introduction to Titration

Understanding Basic Definitions

  • Titration is a method in chemistry used to determine the concentration of a solution.
  • The solution of unknown concentration is called the analyte or the titrand.
  • An accurately measured volume of this solution is then titrated, that is, added, with a reagent of known concentration, also referred to as the titrant.
  • The point at which all of the analyte has reacted with the titrant is the end point of the titration.
  • The equivalence point is theoretically the same volume as the end point and is defined as the point where all the analyte has been exactly consumed by the titrant.
  • Indicators are used to determine when all the analyte has been neutralised during acid-base titrations.

Types of Titrations

  • Acid-Base Titration: The most common type of titration where an acidic solution (analyte) reacts with a basic solution (titrant) or vice versa.
  • Redox Titration: A titration which involves a redox reaction (oxidation-reduction) between the analyte and titrant.
  • Complexometric Titration: This method is used to identify the concentration of divalent metal ions in solution.
  • Precipitation Titration: A method where a precipitate forms during the course of titration.

Process of Titration

  • Titration begins with the preparation of a suitable solution, followed by the addition of the burette with the titrant.
  • The titrant drop by drop falls into the analyte till the endpoint is reached.
  • The volume of the titrant required to reach the endpoint is measured using the burette.
  • This measurement, combined with knowledge of the titrant concentration and stoichiometry of the reaction, allows us to calculate the concentration of the analyte.

Choosing an Indicator

  • An appropriate indicator is chosen, which changes colour at the equivalence point of the reaction. The choice of the indicator is crucial and depends on the nature of the reaction.
  • Phenolphthalein and bromothymol blue are common indicators used in acid-base titrations.
  • The pH range over which the indicator changes colour determines its suitability for a particular titration.

Importance of Titration

  • Titration methods are used in a variety of scientific fields, including environmental science, food quality testing, medicine, and many others.
  • It allows scientists and researchers to determine the exact concentration of a solution, which is essential for many experimental outcomes.
  • Titrations also help check the quality and standards of various products such as water and medicine in the pharmaceutical industry.