Introduction to Acid-Base Titration
An acid-base titration is a laboratory procedure used to determine the concentration of an unknown acid or base by precisely reacting it with a solution of a known concentration (the titrant). This quantitative analysis technique relies on the neutralization reaction that occurs when an acid and a base are mixed.
Key Principles and Components
The core principle involves adding a titrant of known concentration and volume to a solution of unknown concentration until the equivalence point is reached. This point signifies that the moles of acid and base are chemically equivalent. Indicators, which change color at a specific pH, or pH meters are used to detect this equivalence point, often visualized as an endpoint.
A Practical Example
To determine the unknown concentration of hydrochloric acid (HCl), a scientist would slowly add a sodium hydroxide (NaOH) solution of known concentration (e.g., 0.1 M) from a burette into a flask containing the HCl and a few drops of a pH indicator like phenolphthalein. When the solution in the flask changes color (e.g., from colorless to faint pink), the titration is complete, and the volume of NaOH used is recorded to calculate the HCl concentration.
Importance and Applications
Acid-base titrations are crucial in many fields, including environmental monitoring (e.g., measuring water alkalinity), pharmaceutical analysis (determining drug purity), and food science (measuring acidity in products). They provide a precise and relatively simple method for quantitative analysis, essential for quality control and research.