The amount of ascorbic acid, C6H8O6, in orange juice was determined by oxidizing the ascorbic acid to dehydroascorbic acid, C6H6O6, with a known excess of I3–, and back titrating the excess I3– with Na2S2O3. A 5.00-mL sample of filtered orange juice was treated with 50.00 mL of excess 0.01003 M I3–. After the oxidation was complete, 12.2722 mL of 0.06729 M Na2S2O3 was needed to reach the starch indicator end point. Report the concentration of ascorbic acid in milligrams per 100 mL.

A chemistry student needs to standardize a fresh solution of sodium hydroxide. She carefully weighs out 51 mg of oxalic acid (H2C2O4), a diprotic acid that can be purchased inexpensively in high purity, and dissolves it in 250 mL of distilled water. The student then titrates the oxalic acid solution with her sodium hydroxide solution. When the titration reaches the equivalence point, the student finds she has used 19.2 mL of sodium hydroxide solution. Calculate the molarity of the student's sodium hydroxide solution.

Chaya the chemistry student carries out a titration by adding an aqueous solution of NaOH to an aqueous solution of the weak acid HY. The images below represent the solutions formed at various points during this titration. (Na+ and H₂O are omitted for clarity.) HY OY &H30+ О ОН A B C Select the image corresponding to each of the following points in Chaya's titration. Before adding any NaOH : -- + Partway to the equivalence point: -- At the equivalence point : -- After the equivalence point: [ → D E y selecting h menu.

A 0.5504-g sample of KHP (potassium hydrogen phthalate, KHC8H4O4; molar mass = 204.22 g/mol) is completely dissolved in enough deionized water to make 50.00 mL of solution. The titration of this solution with a KOH solution requires 20.50 mL of the base (KOH solution) to reach the “end-point”. What is the molar concentration of KOH solution? The reaction occurs as follows:                       KOH(aq)  +  KHC8H4O4(aq)  -->  K2C8H4O4(aq)  +  H2O(l)           (A) 0.2457 M           (B) 0.1315 M           (C) 0.05390 M           (D) 0.03823 M

A CHM 125 student performed the "Redox Titration" procedure as given in the laboratory manual. In this experiment, the titrant solution of potassium permanganate (KMNO4) was used to determine the percentage of sodium oxalate (NazC2O4) in an unknown sample. The net ionic equation for the titration carried out was: 2MnO4 (aq) + 5C20,7(aq) + 16H*(aq) → 2MN²*(aq) + 10CO2(g) + 8H2O(£) The data provided in the table below was acquired. Complete the table and determine the percent of sodium oxalate in the unknown sample based on this one titration. Molarity of KMNO, Titrant Solution: 0.0203 M Trial 1 Weight of Oxalate 0.954 g Unknown Starting Buret Reading: 0.65 mL Ending Buret Reading: 34.85 mL of permanganate sl order to use 35.00 mL of Titrant Used: mmol of MnO4 mmol of 2- Weight of NazC204 in Unknown: Percent of Na,C204 in Unknown: You wer 4-

A 5.00-mL sample of vinegar was pipetted into a flask, two drops of phenolphthalein indicator were added, and the acid was titrated with 45.62 mL of 0.1008 M NaOH. If the density of the pipetted acetic acid solution was 1.004 g/mL, what was the percentage of acetic acid in the sample? MW HOAc =60.1 g/mol

A 4.908-g sample of a petroleum product was burned in a tube furnace, and the SO2 produced was collected in 2% H2 O2. Reaction: SO2 (g) + H2O2 → H2SO4 A 27.00-mL portion of 0.00826 M NaOH was introduced into the solution of H2 SO4, following which the excess base was back-titrated with 15.15 mL of 0.01165 M HCl. Calculate the sulfur concentration in the sample in parts per million. Concentration ppm

A sample weighing 10.91 g containing an unknown amount of H3PO4 was diluted with water and titrated with a standardized concentration of 0.7255 M NaOH. The endpoint was reached after 27.03 mL of the titrant was added. What is the % H3PO4 (97.994 g/mole) in the sample?   H3PO4  +  2 NaOH --> Na2HPO4 + 2H2O   ROUND OFF FINAL ANSWER TO FOUR (4) SIG FIGS

A chemistry student needs to standardize a fresh solution of sodium hydroxide. She carefully weighs out 400. mg of oxalic acid (H,C204), a diprotic acid that can be purchased inexpensively in high purity, and dissolves it in 250. mL of distilled water. The student then titrates the oxalic acid solution with her sodium hydroxide solution. When the titration reaches the equivalence point, the student finds she has used 90.3 mL of sodium hydroxide solution. Calculate the molarity of the student's sodium hydroxide solution. Be sure your answer has the correct number of significant digits.

A student carries out the following titration by adding H2SO4 drop-wise to a solution of Ba(OH)2.H2SO4(aq) + Ba(OH)2(aq) → BaSO4(s) + 2H2O(l)The conductivity of the reaction mixture __  as H2SO4 is added until the equivalence