Questions 3-7. Calculate the pH of the following solutions (all solutions are aq
ID: 545800 • Letter: Q
Question
Questions 3-7. Calculate the pH of the following solutions (all solutions are aqueous, 1 point each). For calculation, show all work and clearly indicate your answer (e.g., circle it or put a box around it) 3. A solution prepared by combining 20 mL of 0.2 M sodium acetate and 40 mL of 0.2M acetic acid (pKa 4.76). 4, A 0.05M solution of boric acid (Ka = 5.8 x 10.10). 5. A 0.05M solution of ammonia (Ka 1.74 x 10). 6. A 0.0025 M solution of sodium hydroxide (NaOH). 7. A 50 mg/mL solution of penicillin VK (potassium salt, MW 389, pKa 2.8).Explanation / Answer
3)
pH = pKa + log [sodium acetate / acetic acid]
pH = 4.76 + log (20 x 0.2 / 40 x 0.2)
pH = 4.46
4)
Ka = 5.8 x 10^-10
pKa = -log Ka
pKa = -log (5.8 x 10^-10)
pKa =9.24
pH = 1/2 [pKa - log C]
pH = 1/2 [9.24 - log 0.05]
pH = 5.27
5)
pKb = 4.76
pOH = 1/2 [pKb - log C]
pOH = 1/2 [4.76 - log 0.05]
pOH = 3.03
pH + pOH =14
pH = 10.97
16)
[OH-] =0.0025 M
pOH = -log [OH-]
pOH = 2.60
pH + POH = 14
pH =11.40
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.