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G-13
The following information summarizes the format that should be used for the NaOH additions:
i)
start to pH ~ 5.2
add NaOH in about ² mL increments.
ii)
pH 5.2 to pH 5.8
add NaOH in about 0.5 mL increments.
iii)
pH 5.8 to pH 11.5
add NaOH in about 2 to 3 DROPS at a time.
(NOTE: In this region only, record data only if the
pH is > 0.2 pH units.)
iv)
pH 11.5 to pH 12.5
add NaOH in about 0.5 mL increments.
v)
pH 12.5 to end
add NaOH in about 2 mL increments.
(Do not add more than 2 mL of NaOH without recording the pH and volume data.)
NOTE:
The end of the pH titration is when 15 to 18 mL of titrant has been added AFTER the
equivalence point.
Before leaving the laboratory, check to make sure that all of your equipment is clean, and back in your drawer.
Remember to turn in one copy of the Observations Sheet before leaving. The second copy of the
Observations Sheet should be kept in your laboratory manual for future reference.
When you have finished all of your titrations, wash all of the waste acetic acid, NaOH and titration
solutions down the drain with a large excess of water. Wash your burets with hot tap water (four times)
and rinse once with deionized water. Leave them at your work station filled with deionized water.
