Question

You are working in a research lab and your boss has found a bottle on the amino acid shelf which bears a partially erased label. All that is visible is the last four letters of the a ino acid: “____nine” She suggests that you titrate a solution of the unknown amino acid in order to narrow down the possibilities. You weigh out 44.5 g of the solid amino acid powder and dissolve it in 500 mL of ddH 2 O. You decide to titrate 50.0 mL of this unknown a ino acid solution with 250 M NaOH The following titration curve results…

Possible amino acids and their MW (g/mol): threonine (119), phenylalanine (165), methionine (149), arginine (175), alanine (89)

(a) How many mmoles of the amino acid are in the 50 mL that you are titrating? (Answer should be: 50 mmoles)

(b) Locate and determine the pKa values of the amino acid? (Answer should be: pKa 1 = 2.3, pKa 2 = 9.7)

(c) What is the molecular weight of the amino acid? What is the amino acid? (Answer should be: 89 g/mol; Alanine)

Please provide steps.

Answer 1