Laboratory Esperiments 343 D, Concentration of Unknown Acid Trial 2 Trial 3 Tria
ID: 1042389 • Letter: L
Question
Laboratory Esperiments 343 D, Concentration of Unknown Acid Trial 2 Trial 3 Trial ! Volume of unknown acid Avcrage molarity of NaOH from above mL of NaOH at equivalence point Molarity of unknown acid Average molarity (show calculations) Standard deviation QUESTIONS 1. What are the largest sources of error in this experiment 2. What is the pi of the soluation obained by NaOH? We assume additive volumes 3. What is the pll of a solution that is 0.75 M in sodium acetate and 0.50 M in acetic acid? (K, for acetic acid is 1.8x10 )Explanation / Answer
(2)
Moles of HCl taken = Molarity*Volume = 0.25*0.030 = 0.0075
Moles of NaOH taken = 0.125*0.030 = 0.00375
Excess moles of HCl = 0.0075-0.00375 = 0.00375
Total Volume = 60 mL = 0.060 L
So,
Final [H+] in the solution = Moles/Volume = 0.00375/0.060 = 0.0625 M
So,
pH = -log(0.0625) = 1.204
(3)
Using Henderson Hasselbach equation:
pH = pKa + log([salt]/[acid])
Putting values:
pH = 4.74 + log(0.75/0.50) = 4.916
Hope this helps !
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.