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In this lab, we will NOT be using a Buret in measuring solution volume.
Note: As you know, burets are the 2nd most precise/accurate volume measuring device with a Volumetric flask being the most precise/accurate instrument. Volumetric flask only records one volume whereas burets can measure various volume but can dispense solution one drop at a time.
You will be using a Well plate as your reaction bucket. Also you will be using a pipette to dispense the acids and base. A separate pipette will be used to put one drop of the pH indicator (phenolphthalein) into each reaction well.
Remember, we are using a pH indicator in order to know when to stop adding in the acid/base that will completely neutralize the acid/base. In order to do this, the Endpoint of the pH indicator needs to equal the Equivalence point of the solution. The equivalence point of the solution is when all the H1+ ions have reacted with a OH1- ion to form H2O1. Since we are using strong acids and base, the equivalence point has a pH of 7.00. This is not true for all acid base titrations.
Complete the following steps for each titration: All solutions are 1.0M except for Vinegar, 20.drops = 1.0mL
Titrating a Strong acid (HCL solution) by a Strong Base (NaOH solution)
1. In one well, add 15 drops of HCL solution. (Record the number of drop and chemical formula in a data table)
2. Add 1 drop of the phenolphthalein solution (via a pipette) to the acid solution (it may become cloudy, it is OK but not part of reaction)
3. Place a toothpick into reaction well (it can not be removed from well)
4. Start adding in the NaOH solution (via a pipette) one drop at a time with stirring (using toothpick) before adding another drop. Make sure that added solution does not hit toothpick before entering solution.
5. Keep track of the number of drops until one drop makes the solution changes color and does not change back even after stirring (color becomes permeant).
6. Record that number of drops and chemical formula in a data table.
Titrating a Strong base (NaOH solution) by a Strong Acid (HCl solution)
7. Repeat Steps 1-6 just reversing the acid and base.
Titrating a Strong acid (H2SO4) by a Strong Base (NaOH solution)
8. Repeat Steps 1-6 replacing HCl with H2SO4 while leaving NaOH the same.
Determining the Molarity of Acetic Acid in Vinegar. (Titrating a Weak Acid with a Strong Base).
9. Repeat Steps 1-6 replacing HCl with H1C2H3O2 while leaving NaOH the same.