What is a Burette?

• A burette is an essential piece of laboratory equipment commonly used in scientific measurements, particularly in chemistry and analytical laboratories.
• By appearance, it resembles a graduated glass tube with a stopcock at the bottom.
• The word “burette” has French origins, coined by the chemist Joseph Louis Gay-Lussac.
• Its primary purpose is to accurately dispense and measure variable amounts of chemical solutions.

Working Principle:

• Burettes deliver a chemical solution with a known concentration into a flask or other container.
• The stopcock valve controls the fluid flow from the burette, allowing precise dispensing either in a steady stream or drop by drop.
• Burettes are particularly handy when dispensing and measuring liquids (and sometimes gases) with high accuracy.

Applications:

• Titration: Burettes play a crucial role in titration, a method used to determine the concentration of an unknown solution (analyte) by reacting it with a known solution (titrant).
  • During titration, the known solution (titrant) is added from the burette to the analyte until the reaction is complete.
  • An indicator signals the endpoint, which is the point of complete neutralization (e.g., acid-base titration).
  • The color change of the indicator determines the endpoint.
• Quantitative Analysis: Burettes are essential for precise fluid dispensing during quantitative analyses.
• Gas Burettes: These are filled with a fluid (e.g., water, oil, or mercury) and measure gas displacement.

Types of Burettes:

• Volumetric Burette:
  • Features a volume scale printed on the burette wall.
  • Contains a stopcock at the end for liquid flow control.
  • Can be made of glass or plastic.
  • Used for both liquid and gas measurements.
• Digital Electronic Burette: Utilizes electronic sensors for accurate measurements.
• Piston Burette:
  • Similar to syringes but with a precision bore and plunger.
  • Delivers measured volumes of liquid.