While performing an HCl titration experiment, how would the results differ if: a

Question

While performing an HCl titration experiment, how would the results differ if:

a. there was still visible undissolved KHP in the flask when we finished the titration. Would the concentration results for the NaOH soulution be higher or lower then expected?

b. the flasks used for standardization in part A were reused in part B without being properly rinsed before adding the HCl solution. Would the concentration results for part B be higher, lower, or unaffected than expected.

c. If you stop the titration right after the solution first became pink but the color disappeared almost immediately, were the expected concentration results for the HCl soultion higher, lower, or unaffected?

d. the volume readings from the buret were consistantly taken at the top edge of the meniscus rather than the bottom? Explain if the concentration calculated for NaOH would be higher or lower than expected?

Explanation / Answer

A - Concentration of NaOH would be lower than expected, because additional KHP was left unreacted in its solid form, with NaOH.

B - The concentration of HCl would be higher, due to excess base (NaOH) present in the flask.

C - More HCl should be added to the solution to get a light pink homogenous mixture. Concentration of HCl is unaffected.

D - The concentration would be higher, due to misreading of the amount of NaOH present. The top of the meniscus would read a lower number than the actual bottom part of the meniscus, thus decreasing the numerical values of your calculations for NaOH

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