Titration: Volumetric Analysis Technique

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Titration is a volumetric analysis technique used to find the concentration of an unknown substance. There are several types of titration but the one used for this experiment is called acid-base titration as the substance we are titrating is acidic. Acid-base titrations are based on the neutralisation reaction between the analyte and the acidic or basic titrant. The analyte is the solution of unknown concentration and the titrant is the solution of accurately known concentration used to determine the concentrations of other solutions. Titration is used in the industry for medicine, wastewater analysis and acid rain analysis. In an acid-base titration, a suitable indicator is added to the analyte. Titrant is added to the solution until the analyte permanently changes colour. The point at which the indicator just changes colour due to an excess amount of base or acid is known as the end point. This differs from the equivalence point where the equivalence point is the point at which the analyte and the titrant is stoichoimetrically equal in the number of moles. This can also be referred to as the point at which all of the analyte has reacted with the titrant. The equivalence point and the end point usually lie very closely together on a titration curve. This is an example of a weak acid-strong base titration curve. As we add more base to the acid, the pH slowly increases. The steep curve indicates the reaction reaching completion. As you can see from the graph, there’s a very small range between the equivalence point and the end point. As such reaching the equivalence point is very difficult to achieve. In this experiment we are titrating “no frills” vinegar with a standardized solution of sodium hydroxide. It is essential that all glassware is properly cleaned and sterilize to acquire accurate results as any contamination may result in inaccurate results. The burette is washed with the titrate as to ensure the concentration of the titrate is...
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