Mr. O
Acid-Base Titration II
Name:
Purpose: Determine the molarity of a NaOH solution by titrating it with a standard HCl solution. Determine the molarity of a sample of white vinegar.
Equipment: Two 50 mL burets, Buret clamp, ring stand, 10 mL graduated cylinder, 250 mL round bottom flask, and goggles
Materials: .1 M HCl, Unknown NaOH solution, phenolphthalein, and white vinegar
Procedure:
Data Table: Part A
Initial
Reading
Final
Reading
Volume
Used
Trial 1
HCl
Trial 2
NaOH HCl
Trial 3
NaOH HCl
Trial 4
NaOH HCl NaOH
Calculations
Part A: On a separate sheet of paper, calculate the molarity of the NaOH for each trial.
M
A
V
A
=M
B
V
B
Calculate the molarity of the base for each trail:
Conclusions and Questions:
1.
What signals the end of titration?
2.
What is a buret?
3.
Use the data below:
Trial 1 Trial 2 Trial 3 Trial 4
Amount of HCl 10.0 mL
Initial NaOH 0.0 mL
10.0 mL
12.2 mL
10.0 mL
23.2 mL
10.0 mL
35.2 mL
Final NaOH 12.2 mL 23.2 mL 35.2 mL 47.7 mL a.
Calculate the volume of NaOH solution used to neutralize 10.0 mL of standard HCl solution in trail 3. Show your work. b.
According to reference Table M, what indicator would be most appropriate in determining the end point of this titration? Give one reason for choosing this indicator. c.
Calculate the average molarity of the unknown NaOH solution for all four trails. Show your work with the proper units. d.
Explain why it is better to use the average data from multiple trials rather than the data from a single trial to calculate the results of the titration.