Question

Calculate the molecular weight of the unknown amino acid with the titration results.

NaOH Concentration: 0.121M

Mass of Unknown Amino Acid: 0.199g

There were three possibilities of unknown amino acids in the lab. Histidine (209.6g/mol), Glycine (75g/mol), Phenylalanine (165g/mol)

Volume	pH
0	4.16
0.36	4.64
0.87	5.01
1.05	5.18
1.48	5.36
1.96	5.5
2.6	5.68
3.21	5.81
4.1	6.01
5.04	6.21
5.77	6.39
6.37	6.58
6.79	6.74
7.58	7.23
7.82	7.44
8	7.69
8.24	7.91
9.02	8.1
9.1	8.29
9.47	8.51
10.01	8.68
10.81	8.88
11.59	9.04
12.34	9.19
13.11	9.37
13.79	9.53
14.52	9.75
15.21	9.99
15.67	10.22
16	10.41
16.4	10.61
17.02	10.82
17.84	11.03
18.71	11.18
21	11.38
23.24	11.55
28.09	11.74
37.29	11.93
44.2	12.03

Answer 1

For this you need tobfirst plot the curve between the given data and how mych of the volume of noah has been consumed to neutralise the given amino acid. The calculate the molarity and hence molar mass of the amino acid.

Pl check the attachments for the further calculation and graph. In the first attachement of the graph, ph on y axis has been plotted against volume of naoh on x axis which tells around 20ml of naoh has been used to neutralise the given amino acid. So in accordance with the data and calculation, the amino acid given is phenylalanine.