Question

Explain whether the technique errors will result in high or low experimental determination of the molar concentration of CH₃COOH in vinegar.

1. A student uses the pipet bulb to blow the last bit of vinegar sample from the tip into the titration flask, after the pipet is drained.

Answer 1

Using a pipet bulb to force the last bit of vinegar into a titration flask introduces additional volume leading to a lower experimental determination of acetic acid concentration in vinegar, as more titrant will be needed to reach the endpoint.

Step-by-step explanation:

A common analytical technique used to measure the concentration of acetic acid (CH₃COOH) in vinegar is through titration analysis. If a student uses a pipet bulb to blow the last bit of vinegar sample from the tip into the titration flask, after the pipet has drained, this could lead to an inaccurate measurement of the vinegar volume. By adding more vinegar than intended, the molar concentration of acetic acid determined experimentally will be lower than the actual concentration because the titration will require more titrant to reach the end point.

During a titration, the precise volume of analyte (vinegar in this case) needs to be known. Any additional volume, such as blowing out excess from the pipet, can introduce errors. It's important to ensure that the technique errors are minimized to achieve a precise determination of the molar concentration of acetic acid in the vinegar sample.