Purpose of the experiment:
In the first part experiment 20 the purpose was to determine the change in pH, concentration of the acidic solutions, and the equilibrium constant for dissociation acid. By using several titrations, pH electrode, and titration plotted curves.
In the second part experiment 21 the purpose was to determine the concentration of a weak acid in vinegar and to determine the equilibrium constant of the weak acid.
Prepare acidic solution
Two bakers labeled on as KHP one as HCl for the first one 40ml of .05 M potassium hydrogen phthalate for the second beaker .1M HCl were added. 25 ml of HCl transferred to a beaker by using volumetric pipet the beaker labeled as beaker 1. 10ml of deionized water and 3 drops of phenolphalin added to beaker 1.the same previous steps did in KHP instead of HCl and the beaker labeled as beaker 2. In 100ml volumetric flask 10 ml of unknown acid solution added. Deionized water added until the mark and mix. 25 ml of diluted unknown acid solution to 100ml beaker by using 25 volumetric pipet. 10ml of deionized water and 3 drops of phenlpthalin indicator the beaker labeled as 3.
Potentiometric titration acid solutions
125 ml of NaOH was obtaining in a beaker and 50 ml of NaOH transfer to buret the tip and the meniscus is at below 0 ml. one magnetic stirring bar placed in a beaker contain one of the known solution on a stir. The pH recorded by using pH electrode before adding NaOH. The solution titrated by 2 ml of NaOH each time and the pH recorded until the color change. These steps were done for the two known solutions and the unknown solution.
10 ml of vinegar placed in 100ml volumetric flask and deionized water added until the mark. The solution transferred in 150 ml beaker labeled as beaker #1. One ml of dilution solution diluted in 100 ml volumetric flask and deionized water added until the mark. Also, the solution transferred to 150 ml baker labeled as beaker 2. One magnetic stirring bar...