# 65 of 214 A2 equivalence 25.00 mL of a solution containing 0.1333 M ammonia (K = 1.76 x 10-5) is to be titrated with 0.1196 M HCI. NH3 + HCI → NH4CI Calculate pH at equivalence point. (Enter your answer to three significant figures. Ignore the dissociation of water.) Answer: #68 HOAc/NaOH preequivalence 25.00 mL of a solution containing 0.0984 M acetic acid (K₂ = 1.75 x 10-5) is to be titrated with 0.1272 M NaOH. CH3COOH + NaOH CH3COONa + H₂O Calculate pH after the addition of 13.8 mL of base. (Enter your answer to three significant figures. Ignore the dissociation of water.) Answer: pH Buffer 1 A buffer solution of pH 4.76 is to be prepared from acetic acid (with Ka = 1.80 x 10-5, sodium acetate and water. What must be the molar ratio of acetate ion to acetic acid in this solution to obtain this pH? Give your answer to 2 decimal places. Answer:

# 65 of 214 A2 equivalence 25.00 mL of a solution containing 0.1333 M ammonia (K = 1.76 x 10-5) is to be titrated with 0.1196 M HCI. NH3 + HCI → NH4CI Calculate pH at equivalence point. (Enter your answer to three significant figures. Ignore the dissociation of water.) Answer: #68 HOAc/NaOH preequivalence 25.00 mL of a solution containing 0.0984 M acetic acid (K₂ = 1.75 x 10-5) is to be titrated with 0.1272 M NaOH. CH3COOH + NaOH CH3COONa + H₂O Calculate pH after the addition of 13.8 mL of base. (Enter your answer to three significant figures. Ignore the dissociation of water.) Answer: pH Buffer 1 A buffer solution of pH 4.76 is to be prepared from acetic acid (with Ka = 1.80 x 10-5, sodium acetate and water. What must be the molar ratio of acetate ion to acetic acid in this solution to obtain this pH? Give your answer to 2 decimal places. Answer:

Chemistry: An Atoms First Approach

2nd Edition

ISBN:9781305079243

Author:Steven S. Zumdahl, Susan A. Zumdahl

Publisher:Steven S. Zumdahl, Susan A. Zumdahl

Chapter14: Acid- Base Equilibria

Section: Chapter Questions

Problem 118CP: Malonic acid (HO2CCH2CO2H) is a diprotic acid. In the titration of malonic acid w ith NaOH,...

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Two acids, each approximately 0.01 M in concentration, are titrated separately with a strong base. The adds show the following pH values at the equivalence point: HA, pH = 9.5, and HB, pH = 8.5. (a) Which is the stronger acid, HA or HB? (b) Which of the conjugate bases, A or B, is the stronger base?
Consider die titration of 50.0 mL of 0.10 M H3A (Ka1 = 5.0 104, Ka2 = 1.0 108, Ka3 = 1.0 1012) titrated by 0.10 M KOH. a. Calculate the pH of the resulting solution at 125 mL of KOH added. b. At what volume of KOH added does pH = 3.30? c. At 75.0 mL of KOH added, is the solution acidic or basic?
Malonic acid (HO2CCH2CO2H) is a diprotic acid. In the titration of malonic acid w ith NaOH, stoichiometric points occur at pH = 3.9 and 8.8. A 25.00-mL sample of malonic acid of unknown concentration is titrated with 0.0984 M NaOH, requiring 31.50 mL of the NaOH solution to reach the phenolphthalein end point. Calculate the concentration of the initial malonic acid solution. (Sec Exercise 113.)
For the titration of 50.0 mL of 0.150 M ethylamine. C2H5NH2, with 0.100 M HCl, find the pH at each of the following points, and then use that information to sketch the titration curve and decide on an appropriate indicator. (a) At the beginning, before HCl is added (b) At the halfway point in the titration (c) When 75% of the required acid has been added (d) At the equivalence point (e) When 10.0 mL more HCl has been added than is required (f) Sketch the titration curve. (g) Suggest an appropriate indicator for this titration.
Consider the following two acids: pKa1 = 2.98; pKa2 = 13.40 HO2CCH2CH2CH2CH2CO2H Adipic acid pKa1 = 4.41; pKa2 = 5.28 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.
Lactic acid is a common by-product of cellular respiration and is often said to cause the burn associated with strenuous activity. A 25.0-mL sample of 0.100 M lactic acid (HC3H5O3, pKa = 3.86) is titrated with 0.100 M NaOH solution. Calculate the pH after the addition of 0.0 mL, 4.0 mL, 8.0 mL, 12.5 mL, 20.0 mL, 24.0 mL, 24.5 mL, 24.9 mL, 25.0 mL, 25.1 mL, 26.0 mL, 28.0 mL, and 30.0 mL of the NaOH. Plot the results of your calculations as pH versus milliliters of NaOH added.
The titration curves for two acids with the same base are shown on this graph. (a) Which is the curve for the weaker acid? Explain your choice. (b) Give the approximate pH at the equivalence point for the titration of each acid. (c) Explain why the pH at the equivalence point differs for each acid. (d) Explain why the starting pH values of the two acids differ. (e) Which indicator or indicators, phenolphthalein, bromthymol blue, or methyl red, could be used for the titration of Acid 1? For the titration of Acid 2? Explain your choices.
Repeat the procedure in Exercise 61, but for the titration of 25.0 mL of 0.100 M pyridine with 0.100 M hydrochloric acid (Kb for pyridine is 1.7 109). Do not calculate the points at 24.9 and 25.1 mL.
Calculate the volume of 0.150-M HCl required to titrate to the equivalence point for each of these samples. (a) 25.0 mL of 0.175-M KOH (b) 15.0 mL of 6.00-M NH3 (c) 15.0 mL of propylamine, CH3CH2CH2NH2, which has a density of 0.712 g/mL (d) 40.0 mL of 0.0050-M Ba(OH)2
When 40.00 mL of a weak monoprotic acid solution is titrated with 0.100-M NaOH, the equivalence point is reached when 35.00 mL base has been added. After 20.00 mL NaOH solution has been added, the titration mixture has a pH of 5.75. Calculate the ionization constant of the acid.
Calculate the volume of 0.225-M NaOH required to titrate to the equivalence point for each of these samples. (a) 20.0 mL of 0.315-M HBr (b) 30.0 mL of 0.250-M HClO4 (c) 6.00 g of concentrated acetic acid, CH3COOH, which is 99.7% pure