Every amino acid has a carboxyl group and an amino group, and each group can exist in an acidic form or a basic form depending on the pH of the solution in which the amino acid is dissolved. The carboxyl groups of the amino acids have `pK_a` values of approximately 2, the protonated amino group have `pK_(a)` values near 9. Therefore, in a very acidic solution (pH near zero), both groups will be in their acidic forms. At a pH of 7, (which is greater than the `pK_(a)` of the protonated amino group), the carboxyl group will be in its basic form and the amino group will be in its acidic form. In a strongly basic solution (say pH=11), both groups will be in the basic form.

Form A(cationic) of an amino acid exists in

Options

A. fairly basic solution
B. fairly acidic solution
C. neutral solution
D. aprotic organic solvent

Answer

B

Explanation

fairly acidic solution