Calculate the pH of a buffer solution prepared by mixing 10 0 mL of 0.25 M ammon

Question

Calculate the pH of a buffer solution prepared by mixing 10 0 mL of 0.25 M ammonia and 15.0 mL of 0.15 M in ammonium chloride. Assume the volume are additive. K_b for ammonia is 1.8 times 10^-5 Calculate the pH of a buffer solution prepared by mixing 15.0 mL of 0.20 M acetic acid and 15.0 mL of 0.20 M sodium acetate. Assume the volumes are additive. K_a for acetic acid is 1.8 times 10^-5 Give a recipe to prepare an acetate/acetic acid buffer having a pH of 4.90 K_a for acetic acid is 1.8 times 10^-5 Give a recipe to prepare a ammonia/ammonium chloride buffer having a pH of 8.50. K_a for ammonia id 1.8 times 10^-5 Sketch the following titration curves, clearly mark the end points then tell what information can be obtained from each a strong/strong base a weak monoprotic acid/strong base a weak diprotic acid/strong base A 25.00 ml. of an oxalic acid (H_2C_2O_4) solution required 40.00 ml. of a 0.09870 M solution of NaOH for complete neutralization to the phenolphthalein end point. What is the molarity of the acid what was the pH of the oxalic acid solution after the addition of 10.00 mL and 30.00 mL of the base. For H_2C_2O_4, Ka1 = 4.2 times 10^-2 and Ka2 = 6.1 times 10^-5

Explanation / Answer

Q6

Find pH for:

V =10 mL of ammonia, M = 0.25 M

mmol of NH3 = MV = 10*0.25 = 2.5 mmol of NH3

for ammonium chloride

V = 15 mL , M = .15 M

mmol of NH4+ = MV = 2.25 mmol of NH4+

so

apply Henderson HAsselbach equation

pOH = pKb + log(NH4+/NH3)

pKb = -log(Kb) = -log(1.8*10^-5) = 4.75

so

pOH =4.75 + log(2.25/2.5) = 4.7042

pH = 14-4.7042 = 9.2958

pH = 9.2958

For all further questions, please post multiple questions in multiple set of Q&A. We ar enot allowed to answer to multiple questions in a single Q&A post.

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.