Part A of the experiment was dedicated to preparing and standardizing NaOH. During Part
A, the aqueous NaOH solution and KHP solution were created. In the NaOH solution, it was
acceptable to use an approximate volume of deionized water compared to an exact volume of water
was because the amount of NaOH was the solution being measured, not the amount of water.
Throughout the experiment, the endpoints and equivalence points of various trials were
taken. The difference between an endpoint and the equivalence point of a titration was that the
equivalence point of a titration was determined when the analyte equals the titrant. The endpoint of
a titration was reached when the solution turns into a different color, this point was usually to the
right of the equivalence point. Ideally, in a perfect solution the endpoint and the equivalence point
were supposed to be the same.
However, the reason that they were different was because the
endpoints don’t always change in color when all of the H+ ions have been neutralized with the OH
_
ions. Since the endpoint is usually calculated when the solution turns into a different color,
discrepancies were usually measured between the difference between the endpoint and
equivalence point. The endpoint for trial 1 of Part A was determined to be 19.9 mL, while the
volume of NaOH titrated at the equivalence point was determined to be 19.6092 mL. The volume at
the equivalence point was more accurate for determining the exact amount of a neutralized species
because the equivalence point represented the point in which the titration has a pH of 7, while the
endpoint represented the point in time where in which the solution changed color. A table
displaying the NaOH volumes at the endpoint and equivalence point of each KHP titration was
shown below.
KHP trial
NaOH volume at endpoint (mL)
(from titration)
NaOH volume at equivalence point (mL)
(from 2
nd
derivative curve)
2

1
19.9 mL
19.6092 mL
2
20 mL
19.6092 mL
The titration and standard derivative graphs for the first two trials were shown below.
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