before beginning a titration, the burnet was not clean. after completing the titration,the student noticed that droplets of the titrant were clinging to the inside surface of the barrel.wolud the molarity be too high or too low?
Based on the information provided, it is likely that the molarity would be too low.
When the buret is not clean before beginning the titration, there may be substances or impurities present on the inside surface of the barrel. These substances can affect the volume of the titrant delivered from the buret, leading to inaccurate measurements and a lower titer value.
Additionally, the presence of droplets of the titrant clinging to the inside surface of the barrel after completing the titration indicates that not all of the titrant was delivered into the conical flask. This incomplete delivery of titrant would result in a lower volume of titrant used in the titration calculation, leading to a lower calculated molarity.
In this case, the droplets of titrant clinging to the inside surface of the barrel will affect the accuracy of the titration. To determine whether the molarity would be too high or too low, we need to understand the mechanism of the titration.
During a titration, a solution of known concentration (the titrant) is used to react with a solution of unknown concentration (the analyte) until the reaction is complete. The point at which the reaction is complete is called the equivalence point. At this point, the moles of titrant added is stoichiometrically equivalent to the moles of analyte present.
In the situation you described, where droplets of the titrant are clinging to the inside surface of the barrel, these droplets do not participate in the reaction and do not contribute to the volume of the titrant added. As a result, the actual volume of titrant added is less than what was indicated by the titration.
Since molarity is defined as the number of moles of solute divided by the volume of the solution in liters, if the actual volume of titrant used is less than indicated, the calculated molarity will be higher than the actual molarity. Therefore, in this scenario, the molarity of the titrant would be perceived as too high.
To avoid this issue, it is important to ensure that the equipment used, in this case, the buret, is clean and free from any residual droplets or substances that could impact the accuracy of the titration. Thoroughly cleaning and drying the buret before conducting the titration can help prevent such errors.