6. A mixture that weighed 1.0105 g may contain NaOH, Na,CO; and NaHCO. It was dissolved in 100 mL of water. It was analyzed by titrating three 25 mL aliquots of the sample with a 0.0902 M HC1 solution, using Phenolphthalein and Bromcresol Green as indicators. The volumes of acid necessary to achieve the color change of the indicators are detailed below: Vt (mL) 37.9 38.0 | Vf tmL) Aliquot 1 15.9 Aliquot 2 16.1 Aliquot 3 15.8 38.1 a) Mention which components exist in the mixture. b) Calculate the percentage of each component in the mixture.

6. A mixture that weighed 1.0105 g may contain NaOH, Na,CO; and NaHCO. It was dissolved in 100 mL of water. It was analyzed by titrating three 25 mL aliquots of the sample with a 0.0902 M HC1 solution, using Phenolphthalein and Bromcresol Green as indicators. The volumes of acid necessary to achieve the color change of the indicators are detailed below: Vt (mL) 37.9 38.0 | Vf tmL) Aliquot 1 15.9 Aliquot 2 16.1 Aliquot 3 15.8 38.1 a) Mention which components exist in the mixture. b) Calculate the percentage of each component in the mixture.

Fundamentals Of Analytical Chemistry

9th Edition

ISBN:9781285640686

Author:Skoog

Publisher:Skoog

Chapter20: Applications Of Oxidation/reduction Titrations

Section: Chapter Questions

Problem 20.26QAP

See similar textbooks

Similar questions

The arsenic in a 1.010 g sample of a pesticide was converted to H3AsO4 by suitable treatment. The acid was then neutralized, and exactly 40.00 mL of 0.06222M AgNO3 was added to precipitate the arsenic quantitatively as Ag3AsO4. The excess Ag in the filtrate and in the washings from theprecipitate was titrated with 10.76 mL of 0.1000MKSCN; the reaction wasAg+ + SCN-→ AgSCN(s) Calculate the percent AsO3 in the sample.
As part of a soil analysis on a plot of land, a scientist wants to determine the ammonium content using gravimetric analysis with sodium tetraphenylborate, Na+B(C6H5)4−. Unfortunately, the amount of potassium, which also precipitates with sodium tetraphenylborate, is non‑negligible and must be accounted for in the analysis. Assume that all potassium in the soil is present as K2CO3 and all ammonium is present as NH4Cl. A 5.095 g soil sample was dissolved to give 0.500 L of solution. A 150.0 mL aliquot was acidified and excess sodium tetraphenylborate was added to precipitate both K+ and NH4+ ions completely. B(C6H5)4-+K+⟶KB(C6H5)4(s) B(C6H5)4-+NH4+⟶NH4B(C6H5)4(s) The resulting precipitate amounted to 0.269 g. A new 300.0 mL aliquot of the original solution was made alkaline and heated to remove all of the NH4+ as NH3. The resulting solution was then acidified, and excess sodium tetraphenylborate was added to give 0.129 g of precipitate. Find the mass percentages of NH4Cl and…
To determine the fluoride content in an aqueous and chloride-containing preparation of ammonium fluoride, the following analysis was performed. 105.2 mg of the preparation was dissolved in 100.0 mL of water. Then a 300 mL 40 mM lead chloride solution was added, whereby all fluoride ions were precipitated out of the solution in the form of the sparingly soluble salt PbClF (s). The precipitate was separated and washed at 15 degrees with a lead fluoride chloride saturated solution and dried at 130 degrees. The precipitate weighed 651.3 mg. a) Calculate the fluoride content (as % by weight F) in the preparation.b) Determine the purity of the ammonium fluoride preparation
A Medical Technology student was given a capsule of a multivitamins and she was asked to determine the % by mass (w/w) of ascorbic acid present in the capsule. The student analyzed the 2.001 g sample using volumetric titration. The following data was generated in the analysis: KIO3 + 5KI + 6H+ → 3I2 + 6K+ + 3H2O C6H8O6 + I2 → C6H6O6 + 2I- + 2H+ Table 1. Standardization of KIO3 Molarity of Ascorbic Acid Standard Solution 0.03542 M Volume of Ascorbic Acid 25.00 mL Volume of KIO3 8.70 mL Molarity of KIO3 ______________M Table 2. Determination of Ascorbic Acid Concnetration Initial burette reading, KIO3 0.00 mL Final burette reading, KIO3 33.60 mL Volume consumed, KIO3 33.60 mL MM of Ascorbic Acid 176.12 g/mole choices 7.30% 30.1% 33.6% 32.5%
The protein content of wheat flour can be determined reasonably accurately by multiplying the percentage of nitrogen present by 5.7. A 2.06-g sample of flour was taken through a Kjeldahl procedure and the ammonia produced was distilled into a boric acid solution. If this solution required 34.70 mL of 0.174 N HCl for titration to the methyl red end point, what is the a) % Nitrogen and b) % protein in the flour? (Use 1:1 stoich ratio between N and HCl)
The arsenic in a 1.203-g sample of a pesticide was converted to H3AsO4 by suitable treatment. The acid was then neutralized, and 40.00 mL of 0.05871 M AgNO3 was added to precipitate the arsenic quantitatively as Ag3AsO4. The excess Ag+ in the filtrate and in the washings from the precipitate was titrated with 9.63 mL of 0.1000 M KSCN, and the reaction was. Find the percentage of As2O3 in the sample.
1ml of 1mg/ml of diluted aspirin powder solution is titrated by 0.005M NaOH. Before titration, 5 ml ethanol, 14 ml CO2 free water, and 4 drops bromothymol blue indicator is added into diluted aspirin powder solution. Mass of 0.005M NaOH used is obtained by weight titration = 1.1384g . [Molar mass of aspirin =180.15]; for solution, 1g=1mL at 25 degree Celcius. Calculate the purity of the powder.
A metal M forms a water-soluble hydroxide with a chemical formula of MOH. To determine whatM is, a student prepared 250.0 cm3 of MOH standard solution by dissolving 1.17 g of MOH in distilled water. Then the student titrated 25.0 cm3of the solution with 0.055 M H2SO4(aq) usingphenolphthalein as indicator. The titration was repeated several times and the mean titre was 18.85cm3.(a) Describe how the 250.0 cm3 of MOH standard solution was prepared. (b) (i) Calculate the molar mass of MOH. (ii) Determine what M is. (Relative atomic masses: H = 1.0, O = 16.0) THANKYOU!!!
The solubility of borax, which is made up of sodium tetraborate (Na2B4O5(OH)4 8H2O), was analyzed. The dissolution of borax is: Na2B4O5(OH)4 • 8H2O(s) ⇌ 2 Na+(aq) + B4O5(OH)42–(aq) + 8 H2O(l) A 50 mL saturated solution was prepared. After filtration of solution, 5 mL aliquot was transferred to a flask and titrated using 0.432 M HCl. The endpoint was found to be 4.73 mL of the titrant. Tetraborate anion (B4O5(OH)42-) is a weak base which reacts with HCl like the following reaction: B4O5(OH)42–(aq) + 2 H+(aq) + 3 H2O(l) ⇌ 4 H3BO3(aq) What is Ksp expression for the dissolution? What is the tetraborate ions concentration in the filtrate? What is the molar solubility and Ksp of borax if the titration was done at room temperature (298 K)?
a) What mass of Fe(NH4)2(SO4)2•2H2O(s) is required to prepare a 500 mL solution containing 100 ppm (m:v) in Fe? b) Using this stock solution, what aliquot must be used to prepare calibration solutions, 100 mL volume, of the following concentrations: 0.100 ppm, 0.500 ppm, 2.00 ppm, 4.00 ppm, and 7.00 ppm.
a 10g soil sample was gently stirred with 250 ml of 1.0 M CH3COO(NH4) solution for 24 h and centrifuged to separate the solution. The solution recovered after centrifugation was titrated with distilled water to a volume of 1 liter and analyzed for cations. Analytical results showed that the solution contained 20 mg/L Ca, 2 mg/L Mg, 1 mg/L K, and 0.5 mg/L Na. Calculate the number of cation exchange equivalents and express it in meq/100 g of soil
Mr. Clean recently bought a laboratory-grade sodium carbonate from a chemical company known as Brand X. He was supposed to use it in the production of detergents. Unfortunately, he was scammed by the company. He suspected that he purchased a crude sodium carbonate so he tasked the Quality Assurance Department to determine the components of the purchased chemical. The chemist assigned to analyze the sample used double indicator method. For the standardization of HCl titrant, 0.1025 g Na2CO3 of 99.5% purity (FW: 106.00) required 8.20 mL of the titrant to reach the phenolphthalein endpoint. FW: NaOH (40.00), NaHCO3 (84.01), Na2CO3 (106.00) a. What is the molarity of the titrant? The chemist obtained a 3.150 g sample and dissolved it in distilled water to produce a 50.0 mL solution. An aliquot of 10.00 mL was obtained and diluted in a 100.0 mL volumetric flask. A 50.00-mL aliquot of the diluted sample was taken and it required 25.70 mL of titrant for the methyl orange endpoint, while…