Based on the table below: 1). create a titration curve of pH vs. volume NaOH in Excel. Indicate on graph the location of each pKa (pka1, pKa2, pKaR) , first and second equivalence point and pI. Show all your calculations.
2). 1st derivative plot of ΔpH / Δvol NaOH an the y-axis and average vol NaOH on the x-axis (graph in Excel). Highlight (label) the equivalence points
- volume of NaOH on maximum inflection point 1 and point 2.
- What pH range(s) would your unknown serve as an effective buffer?
- Identify your unknown
- At what pH does your amino acid carry a net charge of 0? Draw the structure
Table 1.2 - Titration of an unknown amino acid with NaOH
Vol. NaOH (mL) pH
0.00 2.12
1.00 2.14
2.00 2.12
3.00 2.25
4.00 2.32
5.00 2.38
6.00 2.44
7.00 2.51
8.00 2.61
9.00 2.72
10.00 2.80
11.00 3.09
12.00 3.53
13.00 4.70
14.00 5.21
15.00 5.50
16.00 5.68
17.00 5.84
18.00 5.95
19.00 6.07
20.00 6.18
21.00 6.31
22.00 6.40
23.00 6.54
24.00 6.67
25.00 6.82
26.00 7.00
27.00 7.27
28.00 7.68
29.00 8.17
30.00 8.58
31.00 8.71
32.00 8.88
33.00 9.00
34.00 9.14
35.00 9.27
36.00 9.41
37.00 9.49
38.00 9.60
39.00 9.70
40.00 9.83
41.00 9.95
42.00 10.10
43.00 10.20
44.00 10.57
45.00 10.89
46.00 11.12
47.00 11.32
48.00 11.48
49.00 11.55
50.00 11.65
51.00 11.71
52.00 11.78
53.00 11.82
54.00 11.86
55.00 11.91
56.00 11.95
57.00 11.97
58.00 11.99
59.00 12.00