Solution added in Ascorbic acid Glvcine Volume used (mL) Titration 2 15.90 14.70

Question

Solution added in Ascorbic acid Glvcine Volume used (mL) Titration 2 15.90 14.70 0.60 0.60 pH Titrationl 15.60 14.80 0.70 0.50 Average 15.75 14.75 0.65 0.55 1.52 7.35 1.57 6.33 Glycine + CuSO4 Carboante + CuS04 Questions: 1. Explain the difference in the results between the ascorbic acid-glycine and the ascorbic acid carbonate buffers, and the effect of pH on ascorbic acid. 2. Explain the difference in the results between the ascorbic acid-glycine buffer and the ascorbic acid-glycine buffer CuSO4. between ascorbic acid- carbonate buffer and the ascorbic acid carbonate buffer + CuSO4 model systems

Explanation / Answer

1. Glycine is a neutral amino acid at 5.97(pH).So at 1.7 pH,it is quite acidic and thus takes more volume compared to Carbonate to make buffers.Carbonate on the other hand is the conjugate base of H2CO3 which is a very weak acid and more basic compared to Glycene.Hence it requires less volume to make the salt and acid mixture(Buffer Solution).

2.Presence of CuSO4 makes a drastic difference in volume change as here CuSO4 plays a pivotal role.

CuSO4*5H20 + C6H8O6 = Cu+ + H2SO4 + C6H6O6 + H2O

CuSO4 is in +2 state here and after reaction with Ascorbic acid it converts into Cu(I)(+1 oxidation state) and precipapted out of the solution as Cu(HSO4) and ascorbic acid is converted into dehydroascorbic acid.So combining both glycine and CuSO4 or Carbonate-CuSO4 rapidly decreases the volume required for buffer solution.

Related Questions

Navigate

• Browse (All)
• Browse S
• Subjects

---

---

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