Smith performed a series of acid-base reactions to determine the percentage (by mass) of
the acid in his vinegar. 25.49 mL of NaOH were required to neutralize 0.5208 g of KHP (molar
mass = 204.22 g/mol) dissolved in water. This titration served to standardize the NaOH.
The vinegar solution for titration was prepared in the following manner: A volume of 25.0 mL
of vinegar (density = 1.00 g/mL ) was diluted to 250.0 mL in a volumetric flask, and 25.0 mL of
this diluted solution required 22.62 mL of the above standardized NaOH to reach the
phenolphthalein endpoint. Show your calculations in detail for each question below.
What was the molarity of the NaOH solution used?
(b) What is the percentage by mass of the acid in the original vinegar sample?
C. Prepare the Data Section
Prior to the start of lab, prepare the Data Section of the lab notebook, beginning with the next
page after the Pre-lab Questions/Activities. Format this section for the collection of data and
observations during the lab, as shown below. You will not submit the empty data pages as part of
the Pre-lab (Introductory Statement and Pre-lab Questions/Activities) but the Data Section must
be formatted before coming to lab.
In your laboratory notebook, copy the format and tables below; enter the first three columns of data
in Parts I and Il during the laboratory session, as described in the Procedure Section.
rt I: Preparation and Standardization of NaOH
of NaOH (M)
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