Experiment 18 Prelaboratory Assignment Dohe Potentiometric A

Experiment 18 Prelaboratory Assignment Dohe Potentiometric Analyses Lob Sec. Name Ronat cape in the solution at the stoichiometric poist? strong base (eg., NOH), what species Gontmolecules) CH 3 CO DH, CHCDD\". Nar Are present @ Stocnionem c pon b. For a weak acid (o.g.. CHCOOH) that is titrated are present in the solution at the halfway poist in the dtration toward the soichiometrie point with a strong base (e.g. Naot), what species (ionsmolocules) 2. Briefly explain how the pk, for a weak acikd is determined in this 3. A 23.74-mL volume of 0.0981 M NaOH was used so titrate 25.0 mL of a weak monopeotic acid solution to the sto- chiometric point. Determine the molar concentration of the weak acid solation. Express your answer so the corect number of significant figures.,M,Vi-Hz). 2570491 :2s-y Data in the following table were obtained for the titration of a 0297-g umple ofil. mon proce weak acid with 0.150 M NaOH solution Plot (at right) pH (ordinate) vs V (abscissa) a, Todetermine the molar mass and the pK, of a solid, mnogetic weak 4 a titration of the weak acid with standardized NaOH solution peovided the following data in the table. pH 5 1.96 2.22 s 2.46 2.77 3.06 3.29 3.60 4.26 Vuou added (mL) 0.00 2.00 7.00 10.00 12.00 14.00 16.00 17.00 18.00 20.00 25.00 11.08 11.67 2.05 12.40 IJ Poin. 75 2 @ Skich ,bn e mc Experiment 18 233 K OH 119

Solution

Ans 1 :

When the acetic acid reacts with NaOh , the reaction is given as :

CH3COOH + NaOH = CH3COONa + H2O (l)

At the stoichiometric point , the species present in the solution will be : CH3COOH , CH3COO^- and Na⁺.

The species present in the hathway towards the stoichiometric point will be :

CH3COOH , CH3COO^- , Na⁺ , H3O⁺ , OH^- , H2O