Question

500mg of a mon-amino monocarboxylic acid requires 8.54 milli-equivalents of acid and base in the titration range of pH 0.8 to 12.0. Calculate the molecular weight of this amino acid and determine its identity.

This is probably a difficult question but any help is welcome! I don't understand where to begin.

Answer 1

Milliequivalents = Mass (in Mg) / Equivalent mass

Since it requires 8.54 milli-equivalents of acid and base in the titration range ---> it means 8.54 milliequivalents of

amino acid reacts with 8.54 miliequivalents of acid and base

Total milliequivalents required = 8.54

8.54 = 500 / Equivalent mass

58.548 = Equivalent mass

Since it contains two --> one acid and one amino group

Molar mass = Equivalent mass * NO of acid and amino groups

Molar mass = 58.548 *2 = 117.096 gms /mol

Amino acid is Valine -->