What is Volumetric Analysis?
Volumetric analysis is a quantitative analytical method which is used widely. As the name suggests, this method involves measurement of the volume of a solution whose concentration is known and applied to determine the concentration of the analyte.
In other words, measuring the volume of a second substance that combines with the first in known proportions is known as Volumetric analysis or titration.
A typical titration starts with a beaker or flask containing a precise volume of the analyte and small amount of indicator placed underneath a calibrated burette or pipette containing the titrant.
Small quantities of titrant are added to the analyte and indicator till the indicator changes color in reaction to the titrant saturation threshold reflects the arrival at the endpoint of the titration.
Based on the desired endpoint, single drops or less than a drop of the titrant makes a difference between a permanent and temporary change in the indicator.
The basic principles of volumetric analysis are mentioned below
- The solution to be analyzed contains an unknown amount of chemicals.
- The reagent of unknown concentration reacts with a chemical of an unknown amount in the presence of an indicator (mostly phenolphthalein) to show the end-point. It’s the point indicating the completion of the reaction.
- The volumes are measured by titration which completes the reaction between solution and reagent.
- The volume and concentration of reagent which are used in the titration show the amount of reagent and solution.
- The amount of unknown chemical in the specific volume of solution is determined by the mole fraction of the equation.
When the endpoint of the reaction is reached, the volume of reactant consumed is measured and applied to carry volumetric analysis calculations of the analyte by the following formula,
Ca= Ct Vt M / Va
Ca is the analyte concentration, typically in molarity.
Ct is the titrant concentration, typically in molarity.
V is the volume of the titrant which is used, typically in liters.
M is the mole ratio of the analyte and reactant from the balanced equation.
V is the volume of the analyte, typically in liters.
Many non-acid-base titrations are needed a constant pH throughout the reaction. Therefore, a buffer solution can be added to the titration chamber to maintain the pH value.