b). What is the conjugate base of NH4?c) The Ka for NH4* is 5.5x10-10. What is the pKa for its conjugate base? pKa=d) AlCl3, when dissolved in water, forms a(n) (basic or acidic) solution (Circle one).Calculate the pH at the equivalence point for the titration of 0.120 M hydrofluoric acid (HF) with0.120 M NaOH. The K, of HF is 6.8×104. (Know how to do both acid and base)

b) Conjugate base is formed when a species releases a proton (H+).NH4+ →−H+ NH3so, conjugate base of…

Answered: b). What is the conjugate base of NH4?…

Introductory Chemistry For Today

8th Edition

ISBN:9781285644561

Author:Seager

Publisher:Seager

Chapter9: Acids, Bases, And Salts

Section: Chapter Questions

Problem 9.117E

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Similar questions

Cacodylic acid, (CH3)2AsO2H, is a toxic compound that is a weak acid with pKa = 6.19. It is used to prepare buffered solutions. Calculate the masses of cacodylic acid and sodium cacodylate that should be used to prepare 500.0 mL of a pH = 6.60 buffer so that the buffer has a total of arsenic-containing species equal to 0.25 M, that is, so that: [(CH3)2AsO2H] + [(CH3)2AsO2] = 0.25 M
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.
A buffer is composed of formic acid and its conjugate base, the formate ion. (a) What is the pH of a solution that has a formic acid concentration of 0.050 M and a sodium formate concentration of 0.035 M? (b) What must the ratio of acid to conjugate base be to have a pH value 0.50 units higher than the value calculated in part (a)?
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.
1. A buffer solution is prepared by taking 0.25 moles of acetic acid (pKa = 4.76) and 0.400 moles of barium acetate in sufficient water to make 1.400 liters of solution. Calculate the pH of this solution. a. 4.25 b. 4.45 c. 5.00 d. 5.27 e. 5.35 2. You have 500.0 mL of a buffer solution containing 0.30M acetic acid and 0.20M sodium acetate. What will be the pH of this solution after the addition of 20.0mL of 1.00M HCl solution? (Ka = 1.8 x 10^ -5). a. 4.74 b. 5.07 c. 4.00 d. 3.02 e. 4.42 3. 40.0mL of 0.10M HCl was added to 50.0 mL of 0.10M NaOH and the mixture was stirred, then tested with a pH meter. What is its pH at 25.0 C? a. 1.96 b. 2.00 c. 7.00 d. 11.90 e. 12.05
B) What is the pH at the equivalence point? C) Give the Ka and pKa value of the acid. Explain.
A. What two compounds would be best to use in preparing a pH 9.0 buffer solution? justify your answer. Assume you have the acids and the sodium salts of their conjugate bases available to you. Answer: The two compounds best fo preparing a buffer solution with a pH of 9.0 would be hydrocyanic (HCN) and phenol (HOc6H5) because their pKa values are 9.40 and 9.80 respectively making their pH levels the closest to 9. B. WHat mass ration of sodium to acid is needed to prepare this buffer? C. Can this buffer solution better resist pH changes from a string acid addition or strong base addition?
An analytical chemist is titrating 199.2 mL of a 0.3400 M solution of formic acid (H2CO2) with a 0.4000 M solution of NaOH. The pK, of formic acid is 3.74. Calculate the pH of the acid solution after the chemist has added 185.0 mL of the NaOH solution to it. Note for advanced students: you may assume the final volume equals the initial volume of the solution plus the volume of NaH solution added, Round your answer to 2 decimal places.
The desired pH is 6.4 in creating a buffer system/buffer solution of about 50-60mL. Therefore, a student picks Silicic Acid Si(OH)4, as 1mL of 1M of the acid has a pH of 6.4, which also has a pKa of 9.82. What is the ratio HA/A- and ratio A-/HA-? The buffering capacity will be checked by the addition of 1mL of 1M HCl or 1mL of 1M NaOH and should not change by more than 0.25pH units.
1) A buffer solution is 0.337 M in H2CO3 and 0.239 M in KHCO3 . If Ka1 for H2CO3 is 4.2x10^-7 , what is the pH of this buffer solution? pH = 2) An aqueous solution contains 0.302 M hypochlorous acid. How many mL of 0.231 M potassium hydroxide would have to be added to 150 mL of this solution in order to prepare a buffer with a pH of 7.540? 3) 36.5 mL sample of a 0.310 M aqueous hypochlorous acid solution is titrated with a 0.441 M aqueous barium hydroxide solution. What is the pH after 8.80 mL of base have been added? Ka for HClO is 3.5x10^-8 . pH =
Salts containing the phosphate ion are added to municipalwater supplies to prevent the corrosion of lead pipes. (a) Basedon the pKa values for phosphoric acid (pKa1 = 7.5 x 10 - 3,pKa2 = 6.2 x 10 - 8, pKa3 = 4.2 x 10 - 13) what is the Kbvalue for the PO43 - ion? (b) What is the pH of a 1 x 10 -3 M solution of Na3PO4 (you can ignore the formation ofH2PO4- and H3PO4)?
If the concentration of the weak base ammonia is 0.10 M and it is titrated with 0.1 M HCl, and the Kb of ammonia is 1.8 x 10^-5, calculate the pH at 1/2-way to the equivalence point.

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