1. While titrating, a student added 45 mL of NaOH solution without ever seeing a color change. Suggest at least two possible reasons that this might occur. 2. While titrating, a student added 0.5 mL of NaOH and observed an intense color change. Suggest at least one possible reason that this might occur. 3. A student completed two trials of titration with a very faint pink color, and one that was a very bright, intense pink color. What should the student do at that point? 4. The AGxn value for this reaction is different than the value you calculated in this experiment. Explain why the two values are different. (You may need to consult your textbook. See Chapter 18, relating AG xn to AG xn at nonstandard states and to Keq). 8

1. While titrating, a student added 45 mL of NaOH solution without ever seeing a color change. Suggest at least two possible reasons that this might occur. 2. While titrating, a student added 0.5 mL of NaOH and observed an intense color change. Suggest at least one possible reason that this might occur. 3. A student completed two trials of titration with a very faint pink color, and one that was a very bright, intense pink color. What should the student do at that point? 4. The AGxn value for this reaction is different than the value you calculated in this experiment. Explain why the two values are different. (You may need to consult your textbook. See Chapter 18, relating AG xn to AG xn at nonstandard states and to Keq). 8

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter15: Acid-base Equilibria

Section: Chapter Questions

Problem 76E: Methyl red has the following structure: It undergoes a color change from red to yellow as a solution...

See similar textbooks

Similar questions

Consider the following two acids: In two separate experiments the pH was measured during the titration of 5.00 mmol of each acid with 0.200 M NaOH. Each experiment showed only one stoichiometric point when the data were plotted. In one experiment the stoichiometric point was at 25.00 mL added NaOH, and in the other experiment the stoichiometric point was at 50.00 mL NaOH. Explain these results. (See Exercise 113.)
Another way to treat data from a pH titration is to graph the absolute value of the change in pH per change in milliliters added versus milliliters added (pH/mL versus mL added). Make this graph using your results from Exercise 61. What advantage might this method have over the traditional method for treating titration data?
If 55 mg of lead(II) sulfate is placed in 250 mL of pure water, does all of it dissolve? If not, how much dissolves?
Describe how the amount of sodium hydroxide in a mixture can be determined by titration with hydrochloric acid of known molarity.
Calculate the pH after 0.020 mole of NaOH is added to 1.00 L of each of the solutions in Exercise 22.
Calculate the pH after 0.020 mole of NaOH is added to 1.00 L of each of the four solutions in Exercise 21.
7. Describe a buffered solution. Give three examples of buffered solutions. For each of your examples, write equations and explain how the components of the buffered solution consume added strong acids or bases. Why is buffering of solutions in biological systems so important?
Explain why barium fluoride dissolves in dilute hydrochloric acid but is insoluble in water.
Methyl red has the following structure: It undergoes a color change from red to yellow as a solution gets more basic. Calculate an approximate pH range for which methyl red is useful. What is the color change and the pH at the color change when a weak acid is titrated with a strong base using methyl red as an indicator? What is the color change and the pH at the color change when a weak base is titrated with a strong acid using methyl red as an indicator? For which of these two types of titrations is methyl red a possible indicator?
Calculate the pH after 0.020 mole of HCl is added to 1.00 L of each of the four solutions in Exercise 21.
You are given the following acidbase titration data, where each point on the graph represents the pH after adding a given volume of titrant (the substance being added during the titration). a What substance is being titrated, a strong acid, strong base, weak acid, or weak base? b What is the pH at the equivalence point of the tiration? c What indicator might you use to perform this titration? Explain.