Calculate the pH at the stoich iometric po int of the titration of 25.00 cm3 of 0.150 M lactic acid with 0.188 M NaOH(aq) .

Hydrogen peroxide solutions can easily be decomposed by dust, trace amounts of metals or light. It istherefore necessary to periodically determine the purity of the peroxide solutions.This can be done via a redox titration as follows: The density of a particular surgical grade hydrogen peroxide solution is 1.11g.cm-3.  Exactly 10 mL of this solution was pipetted and quantitatively transferred, along with a sufficientamount of a dilute sulphuric acid solution, into a 250.00 mL volumetric flask and made up to the mark. A 25.00 mL portion of this diluted solution is pipetted into a conical flask, and titrated with a0.372 M KMnO4 solution. The endpoint of the titration is determined when the colourless solution in the conical flask turns apersistent bright pink due to the presence of excess permanganate ions. The average titration value is 26.20 mL of the KMnO4 solution   1.Determine the percentage of the hydrogen peroxide in the solution sample.2. Naturally occurring manganese…

Calculate the pH of a 1.50 M (CH3)3NHBR solution (aq., 25 °C). 3). Kb (CH3)3N = 6.31 x 10-5.

5. Erina observed that the borax she uses to clean the house is only partially soluble with water. She found on the internet that borax is composed of sodium tetraborate (Na,B,0;(OH), • 8H,0) and wanted to analyze its solubility. The dissolution of borax is: Na,B,0;(OH), • 8H20(9 = 2 Na (aq) + B40;(OH), (aq) + 8 H20o A 50.0 mL saturated solution was prepared for the experiment. After filtering the solution, a 5.00 mL aliquot was transferred to a 25.0 mL Erlenmeyer flask and was titrated using pre-standardized 0.4320 M HCI. The endpoint was reached after the addition of 4.73 mL titrant. Since the tetraborate anion (B,0;(OH),?) is a weak base, the tetraborate ion reacts with HCI by the reaction: B,0,(OH), (aq) + 2 H*(aq) + 3 H,0g = 4 H;BO3(aq) a. Write the K, expression for the dissolution process.