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I-5
EXPERIMENTAL PROCEDURE:
Preparation of Burets
NOTE:
In order to reduce the time required for set up and for clean-up, two students may
share one pair of reagent burets. One student will fill a buret with HCl solution while the
other student will fill the second buret with NaOH solution.
a)
Using the correct technique, rinse one buret twice with 8 mL of the HCl solution
discarding each rinse. Fill the buret to a point about the 10 mL mark (do NOT set this
value to 0.00 mL). Record the concentration of this solution on your Observations Sheet.
b)
Using the correct technique, rinse one buret twice with 8 mL of the NaOH solution
discarding each rinse. Fill the buret to a point about the 10 mL mark (do NOT set this
value to 0.00 mL). Record the concentration of this solution on your Observations Sheet.
NOTE:
This experiment is NOT done in pairs. Only the burets are to be shared.
Standardize your pH meter following the appropriate instructions given on pages 25 to 27.
Part I.
Effect of the Addition of a Strong Acid to Deionized Water
1.
Pour 25 mL of deionized water into a 100 mL beaker. Measure and record the pH of the
water using a pH meter.
2.
Add 2 drops of 0.20 M HCl to the water and again measure and record this pH on your
Observations Sheet.
Part II.
Preparation of the Acetic Acid-Acetate Buffer Solution
1.
Record on your Observations Sheet, the pH of the demonstration solutions of
~0.20 M acetic acid (CH3COOH) and the ~0.20 M sodium acetate (CH3COONa)
2.
Using the automatic dispenser add 50.0 mL of the ~0.20 M sodium acetate solution to a
clean dry 250 mL beaker
