There was difficulty in determining the end point in the titration due to the color of the food sample and the titration was stopped before the true endpoint was reached. Would the determined percentage of acetic acid in the food sample be higher or lower due to this error? Explain
The determined percentage of acetic acid in the food sample would likely be lower due to this error.
In a titration, the endpoint is the point at which the reaction between the titrant and the analyte is stoichiometrically complete. It is usually indicated by a color change in the reaction mixture. In the case of determining the acetic acid content in a food sample, a common indicator used is phenolphthalein, which changes color from colorless to pink in the presence of excess base (titrant).
If the color of the food sample itself is similar to the color change of the indicator, it can make it more challenging to determine the endpoint accurately. Therefore, if the color of the food sample closely matches the color change, it is possible that the titration might be stopped prematurely, with the assumption that the endpoint has been reached.
As a result, if the titration is stopped before the true endpoint, it means there is still excess base present, indicating that not all the acetic acid has reacted. This would lead to a lower volume of titrant used, resulting in a lower measured concentration of acetic acid in the food sample.