Conductimetric Titration and Gravimetric Determination of a Precipitate
* Measure the conductivity of the reaction between sulfuric acid and barium hydroxide * use conductivity values to determine equivalence point * measure mass of a product to determine equivalence point gravimetrically * calculate molar concentration of barium hydroxide solution
* First, combine 10.0 mL of the Ba(OH)2 solution with 50 mL of distilled water. Then, measure out 60 mL of 0.100 M H2SO4. Set up a conductivity probe and open programs by connecting to logger pro. After that, start to titrate with increments of 1.0 mL. Keep titrating with smaller increments until it is pretty close to the 100 microsiemens/cm mark.…show more content…
The reactant ions reacted and decreased as more product formed. By measuring the conductivity throughout, the equivalence point was determined. With the equivalence point and the stoichiometric relationship, the molarity of barium hydroxide can be determined. Another way to calculate the molar concentration of barium hydroxide would be to calculate the number of moles of the insoluble barium sulfate by gravimetric determination.
Data Analysis: 1. 7.6 • 10-4 mol H2SO4 2. 0.076 M Ba(OH)2 3. 0.0008351 mol BaSO4 4. 0.0835 M Ba(OH)2 5. Equivalence Point: 24% error, Gravimetric determination: 17% error. The gravimetric determination was more accurate because an exact amount of precipitate was formed.
In this lab an attempt was made to determine the concentration of a Ba(OH)2 solution by using the conductimetrically determined equivalence point of the reaction between Ba(OH)2 and H2SO4 and by gravimetric determination. The molarity using the equivalence point was determined to be 0.076 M, with a percent error of 24% (actual value was 0.100 M). The molarity using gravimetric determination was 0.0835, an error of 17%. One possible error is the presence of bubbles in the buret. Bubbles would have caused the buret reading to be too high, resulting in a larger equivalence point. Another possible error deals with the colloidal nature of barium hydroxide due to its relatively low solubility. The colloidal barium hydroxide would make it