A. What is the pH after the addition of 180.0 mg of HBr? Express your answer using two decimal places. B. Determine the pH of the solution if 50.0 mg of NaOH was added to the initial buffer solution instead of HBr. Express your answer using two decimal places..

A. What is the pH after the addition of 180.0 mg of HBr? Express your answer using two decimal places. B. Determine the pH of the solution if 50.0 mg of NaOH was added to the initial buffer solution instead of HBr. Express your answer using two decimal places..

Principles of Modern Chemistry

8th Edition

ISBN:9781305079113

Author:David W. Oxtoby, H. Pat Gillis, Laurie J. Butler

Publisher:David W. Oxtoby, H. Pat Gillis, Laurie J. Butler

Chapter15: Acid–base Equilibria

Section: Chapter Questions

Problem 95AP

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a. You want to prepare 1.00 L of a buffer solution with a pH of 3.5. You are given an 0.45 M solution of nitrous acid, HNO2, and an 0.68 M solution of NaOH. What volume of each of these solutions must be mixed in order to get the desired buffer solution? Use the simultaneous equations method to solve this problem. b)If the acid used in a. was nitric acid, HNO3, could the same buffer solution be made? Briefly explain. c) If the buffer solution prepared in a. also contained ~10–6M Ni2+ and ~10–6 M Pb2+ , could those metal ions be separated from each other by saturating the solution with H2S? Explain your answer by showing the necessary calculations.
A 1.0 L buffer solution has 0.15 mol L1 HCN and 0.60 mol L-1 KCN. The K, of HCN is 4.9 x 10-10. Which action will destroy the buffer? A. Add 0.50 mol HCN to the buffer. B. Add 0.50 mol KCN to the buffer. C. Add 0.50 mol HCl to the buffer. D. Add 0.50 mol KOH to the buffer. E. More than one of the above will destroy the buffer.
A 1.00 liter solution contains 0.36 moles hydrofluoric acid and 0.28 moles sodium fluoride .If 0.14 moles of hydroiodic acid are added to this system, indicate whether the following statements are true or false.(Assume that the volume does not change upon the addition of hydroiodic acid.) A. The number of moles of HF will remain the same. B. The number of moles of F- will decrease. C. The equilibrium concentration of H3O+ will increase. D. The pH will remain the same. E. The ratio of [HF] / [F-] will remain the same.
A 1.00 liter solution contains 0.36 moles hydrocyanic acid and 0.28 moles potassium cyanide. If 0.14 moles of hydrochloric acid are added to this system, indicate whether the following statements are true or false. (Assume that the volume does not change upon the addition of hydrochloric acid.) ✓ A. The number of moles of HCN will decrease. True B. The number of moles of CN will increase. False C. The equilibrium concentration of H3O+ will remain the same. D. The pH will increase. E. The ratio of [HCN] [CN] will increase.
A 1.00 liter solution contains 0.48 M ammonia and 0.37 M ammonium iodide. If 0.18 moles of hydrobromic acid are added to this system, indicate whether the following statements are true or false. (Assume that the volume does not change upon the addition of hydrobromic acid.) A. The number of moles of NH3 will decrease. B. The number of moles of NH4+ will decrease. C. The equilibrium concentration of H3O+ will decrease. D. The pH will remain the same. E. The ratio of [NH3] / [NH4+] will decrease.
A 1.00 liter solution contains 0.59 M ammonia and 0.45 M ammonium bromide.If 0.23 moles of perchloric acid are added to this system,indicate whether the following statements are true or false.(Assume that the volume does not change upon the addition of perchloric acid.) A. The number of moles of NH3 will increase. B. The number of moles of NH4+ will remain the same. C. The equilibrium concentration of H3O+ will decrease. D. The pH will remain the same. E. The ratio of [NH3] / [NH4+] will remain the same.
4. How could you tell which of the solutions that were able to buffer well against added acid has the greatest buffering capacity against acid? a. Add equal amounts of acid to each solution until the pH of one solution changes significantly. b. Add equal amounts of base to each solution until the pH of one solution changes significantly. c. The solution with the highest pH after adding the 2 ml of acid has the greatest buffering capacity. Explain your answer;
Styles 2. Use a 100-mL beaker to make a 50 ml of the sodium acetate (NaA)/acetate (HA) buffer solution, as shown in the table. Measure and record the pH. Pipette 25 ml of this buffer solution and place it in a new 50-ml beaker. Add 1 ml of 1 M HCI or 1 M NAOH to each separate beaker and mix well. Measure and record pH. Table 2: Buffered solution (acetate) Calculated pH Measured pH 25 mL 1.0 M NaAc + 25 ml 1.0M HA 4.23 4.12 25 ml above mix buffer +1 ml 1.0 M HCI 4.22 25 ml above mix buffer + 1 ml 1.0 M NAOH D, Focus * The pka of acetic acid is 4.75.
4. A 100 mL buffer solution with pH of 4.80 is prepared as a stock solution. Using this stock buffer solution, three buffers are prepared by diluting a given volume of the stock buffer (as shown below) to 100 mL with water. Buffer 1 a. b. e a. E Do they have the same pH? Check the box corresponding your answer. Yes No Which is true about their absolute concentrations? Check the box corresponding your answer. [Buffer 1]> [Buffer 2] > [Buffer 3) [Buffer 3] > [Buffer 2]> [Buffer 1] [Buffer 3] = [Buffer 2] = [Buffer 1) [Buffer 3] = [Buffer 2] > [Buffer 1) [Buffer 3] > [Buffer 2] = [Buffer 1) d. Which of the following is true about the ability of the three buffers to resist pH change when 1 mL of HCI is added to each buffer? Check the box corresponding your answer. Which is true about their concentration ratios? Check the box corresponding your answer. [Buffer 1]> [Buffer 2] > [Buffer 3) [Buffer 3] > [Buffer 2]> [Buffer 1) [Buffer 3] = [Buffer 2] = [Buffer 1) Solution A B C D [Buffer 3] =…
1) A 45 mL sample of 0.175 M KOH is titrated with 0.200 M HI. a. b. c. d. Find the initial pH of the 0.175 M KOH solution. Find the pH when 18 mL of 0.200 M HI have been added. Find the pH when 63 mL of 0.200 M HI have been added. How many milliliters of 0.200 M HI must be added to reach the equivalence point? e. What is the pH at the equivalence point? f. Draw a titration curve for this titration. g. Which of the following indicators should be used to signal the endpoint of this titration: methyl red (pK₁ = 5.5), litimus (pK₁ = 7.0), or phenolphthalein (pK, = 8.7)? Explain.
2. Addition of a small amount of strong acid or strong base to a buffer: effect on pH 3. Add 5 drops of the diluted hydrochloric acid solution (0.1 mol/L) into the test tubes #1 and #3, and 5 drops of the diluted sodium hydroxide solution (0.1 mol/L) into the test tubes #2 and #4. Mix the content of the test tubes and record the color.
18. In carrying out a titration of a potassium hydroxide solution with a standard hydrochloric acid solution, a student misread the volume on the burette. That is, the actual volume recorded was smaller than the volume required to reach the end point. How will this error affect the calculated concentration of the potassium hydroxide solution? The calculated concentration will be larger than the actual concentration. b. The calculated concentration will be smaller than the actual concentration. The calculated concentration will be the correct concentration. а. с. d. There is no way to determine how this error will affect the calculation. The calculated concentration will be the actual concentration. е.