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Ascorbic Acid Titration of Vitamin C Tablets
Procedure – Each Part of lab requires a separate data table. You might want to
put each table on a separate page so you can leave room to show equations and
calculations.
Part A. Preparation of Vitamin C Tablet Solutions
1. Obtain two vitamin C tablets. Place a plastic weighing boat on the balance, and press zero to tare the balance.
Break the first tablet into two pieces so it will dissolve faster, place the pieces in the tared weighing boat, and
record the exact mass of the tablet in your LAB NOTEBOOK. MAKE SURE TO RECORD ALL OF THE
DIGITS! Repeat this procedure for the second tablet in a separate plastic weighing boat. (Note: It would be
best to setup a data table to record masses in your lab notebook, 3 columns x 2 rows.)
2. Transfer the tablets to separate, labeled 250 mL Erlenmeyer flasks. Add 40-50 mL of deionized water to
each sample. Crush each tablet with a stirring rod. Use a hotplate at your lab bench or on the back benches to
heat the flasks (heat setting between 3-4). Heat gently to dissolve the vitamin C tablets. The binder in the
tablet will not completely dissolve, leaving some residue. Allow these solutions to cool to room temperature
while standardizing the NaOH solution in Part B.
CAUTION: Sodium hydroxide, NaOH, can cause chemical burns and damage eyes very quickly.
Any NaOH spilled on your skin must be rinsed immediately with water for 15 minutes. Any
NaOH spilled on the lab benches should be neutralized, and the area rinsed with water and wiped
clean. Inform your instructor of any NaOH spills.
CAUTION: Sulfuric acid, H2SO4(aq), is corrosive and can cause chemical burns and damage
clothing. Any H2SO4(aq) spilled on skin must be rinsed immediately with water for 15 minutes.
Any acid spilled on your work area must be neutralized, the area rinsed with water and wiped
clean.
WEAR GOGGLES AT ALL TIMES, even when you are washing the glassware to avoid exposing
your eyes to NaOH solution. Wash your hands completely with soap and water before leaving the
lab.
Part B. Standardization of the NaOH Solution
1. LAB NOTEBOOK: Prepare a data table in your lab notebook to record volume and concentration data. For
each of the 3 trials performed in Part B, you will need to know the exact volume of sulfuric acid used, the
initial, final, and total volumes of NaOH added to reach the endpoint, the concentration of NaOH calculated
and the average NaOH of the 3 trials. Prepare a data table (with labeled columns and rows) that has all of this
informatin in it.
2. Use the NaOH pump dispenser to deliver 100 mL of NaOH into a clean, labeled 250 mL beaker. Clean,
rinse, and condition a 25.00 mL buret with a few mL of the NaOH solution, then fill the buret with the NaOH
solution. Drain a small amount of the NaOH solution into your waste beaker so it fills the buret tip (with no
air bubbles present). Record the exact initial buret reading. (Save the rest of the NaOH solution in the beaker
to refill the buret later.)
