While it is true that the second titration uses the original NaOH solution, there is an important factor that makes the first titration more reliable. In the first titration, the student used a laboratory balance to accurately weigh the amount of KHP. This method provides a precise measurement of the KHP used in the titration, which allows for a more accurate calculation of the NaOH concentration.
In the second titration, the student diluted the 6 M HCl solution using a graduated cylinder. Graduated cylinders are generally not as precise as other laboratory instruments like volumetric pipettes or burettes. The potential error in measuring the volume of HCl solution could affect the accuracy of the calculated NaOH concentration in the second titration.
Considering these factors, the student should be more confident in the concentration of the NaOH solution from the first experiment, since the more precise weighing method of KHP was used, compared to the potentially less accurate graduated cylinder measurement in the HCl dilution process in the second experiment.
The Question Is:
"A student weighs 0.347 g of KHP on a laboratory balance. The KHP was titrated with NaOH and the concentration of the NaOH determined to be 0.110 M. For the second titration, the student correctly diluted 6 M HCl from the reagent shelf using a graduated cylinder to obtain approximately 0.6 M HCl. This solution was titrated with the original NaOH solution. The student calculated the concentration of NaOH from the experiment to be 0.099 M. In which experiment should the student be more confident of the concentration of the NaOH solution? Why?"
I believe the second titration would be more accurate due to it being titrated with the original amount of NaOH and so im assuming that its concentration would yield a better result. Would that be the case, is there anything im neglecting?
1 answer