The pH of a 0.392 M solution of the conjugate base, A-, of a weak acid,...

The pH of a 0.392 M solution of the conjugate base, A-, of a weak acid, HA, is 11.60. What is the K_b for A-?

Please show work

Expert Solution

pH = 11.60

[ A- ] = 0.392 M

[H+] = 10^-pH

= 10^-11.60

= 2.5 x 10^-12 M

[OH-] = 1.0 x 10^-14 / 2.5 x 10^-12 = 4 x 10^-3 M

A- + H2O ---------------------> AH + OH-

0.392 0 0

0.392-x x x

x = [OH-] = 4 x 10^-3 M

Kb = x^2 / 0.392 -x

kb = (4 x 10^-3)^2 / (0.392 - 4 x 10^-3)

Kb = 4.12 x 10^-5

queen_honey_blossom answered 1 year ago

Calculation of Molar Ratios of Conjugate Base to Weak Acid from pH For a weak acid...

Calculation of Molar Ratios of Conjugate Base to Weak Acid from pH For a weak acid with a pKa of 6.0, calculate the ratio of conjugate base to acid at a pH of 5.0. Choice of Weak Acid for a Buffer Which of these com-pounds would be the best buffer at pH 5.0: formic acid (pKa 5 3.8), acetic acid (pKa 5 4.76), or ethylamine (pKa 5 9.0)? Briefly justify your answer. please show work thank you will rate.

12. In a solution, when the concentrations of a weak acid and its conjugate base are...

12. In a solution, when the concentrations of a weak acid and its conjugate base are equal,…. [A] the system is not at equilibrium [B] the -log of the [H+] and the -log of the Ka are equal [C] the buffering capacity is significantly decreased [D] the buffering capacity is significantly increased [E] All of the above are true. 13. The concentration of iodide ions in a saturated solution of lead (II) iodide is ________ M. The solubility product constant...

Design a buffer that has a pH of 6.55 using one of the weak acid/conjugate base...

Design a buffer that has a pH of 6.55 using one of the weak acid/conjugate base systems shown below. Weak Acid Conjugate Base Ka pKa HC2O4- C2O42- 6.4 × 10-5 4.19 H2PO4- HPO42- 6.2 × 10-8 7.21 HCO3- CO32- 4.8 × 10-11 10.32 How many grams of the sodium salt of the weak acid must be combined with how many grams of the sodium salt of its conjugate base, to produce 1.00 L of a buffer that is 1.00 M...

Design a buffer that has a pH of 4.86 using one of the weak acid/conjugate base...

Design a buffer that has a pH of 4.86 using one of the weak acid/conjugate base systems shown below. Weak Acid Conjugate Base Ka pKa HC2O4- C2O42- 6.4×10-5 4.19 H2PO4- HPO42- 6.2×10-8 7.21 HCO3- CO32- 4.8×10-11 10.32 How many grams of the potassium salt of the weak acid must be combined with how many grams of the potassium salt of its conjugate base, to produce 1.00 L of a buffer that is 1.00 M in the weak base? grams potassium...

Design a buffer that has a pH of 8.25 using one of the weak base/conjugate acid...

Design a buffer that has a pH of 8.25 using one of the weak base/conjugate acid systems shown below. Weak Base Kb Conjugate Acid Ka pKa CH3NH2 4.2×10-4 CH3NH3+ 2.4×10-11 10.62 C6H15O3N 5.9×10-7 C6H15O3NH+ 1.7×10-8 7.77 C5H5N 1.5×10-9 C5H5NH+ 6.7×10-6 5.17 How many grams of the chloride salt of the conjugate acid must be combined with how many grams of the weak base, to produce 1.00 L of a buffer that is 1.00 M in the weak base? grams chloride...

Calculate the conjugate base to acid ratio in the solution. Calculate the theoretical pH. Solution: 10.00...

Calculate the conjugate base to acid ratio in the solution. Calculate the theoretical pH. Solution: 10.00 ml of .2M acetic acid and 1.00 mL of .1 M sodium hydroxide and 9.00 mL distilled water

if you need to prepare a buffer solution at pH 7.4 from a weak base/ conjugate...

if you need to prepare a buffer solution at pH 7.4 from a weak base/ conjugate acid buffer system which buffer system would you pick and why?

A) Why does a buffer solution require a weak acid/base conjugate pair, as opposed to a...

A) Why does a buffer solution require a weak acid/base conjugate pair, as opposed to a strong acid, and its conjugate? A strong acid will completely dissociate, suggesting that the conjugate base is really weak and will not neutralize any additional H+ ions. A strong acid will completely dissociate, suggesting that the conjugate base is really strong and will not neutralize any additional H+ ions. A strong acid will only partially dissociate, suggesting that the conjugate base is really weak...

The pH of a 0.110 M solution of a weak base is 9.69. What is the...

The pH of a 0.110 M solution of a weak base is 9.69. What is the Kb of the base?

A 0.400 M solution of weak base has a pH of 9.85. What is the base...

A 0.400 M solution of weak base has a pH of 9.85. What is the base hydrolysis constant, Kb for the weak base?

Question