Titration is a common laboratory method of quantitative chemical analysis to determine the concentration of an identified analyte. A reagent, termed the titrant or titrator, is prepared as a standard solution of known concentration and volume. The titrant reacts with a solution of analyte to determine the analyte's concentration. The volume of titrant that reacted with the analyte is termed the titration volume.
A burette and Erlenmeyer flask (conical flask) being used for an acid–base titration.
Analysis of soil samples by titration.
Methyl orange
Phenolphthalein, a commonly used indicator in acid and base titration.
A pH indicator is a halochromic chemical compound added in small amounts to a solution so the pH (acidity or basicity) of the solution can be determined visually or spectroscopically by changes in absorption and/or emission properties. Hence, a pH indicator is a chemical detector for hydronium ions (H3O+) or hydrogen ions (H+) in the Arrhenius model.
pH measurement with indicator paper
Hydrangea in acid soil
Hydrangea in alkaline soil
A gradient of red cabbage extract pH indicator from acidic solution on the left to basic on the right