Is the salt of a weak acid and a weak base considered a weak acid or a weak base?

Is the compound iodopyracet aka Diadrast(used to measure renal function) a weak acid or a weak base??? I cannot find this information anywhere!! Bonnie 10/07/99

	Vocabulary
	amine amino acid carboxylic acid weak acid weak base

Here is the structure of iodopyracet, which is the salt of diethanolamine and 3,5-diiodo-4-pyridone-N-acetic acid:

The carboxylate group can accept H⁺ ions. If the pH is low enough, the anion can act as a weak base. The NH₂⁺ group can yield hydrogen ions, so if the pH is high enough, it can act as a weak acid. So the answer to your question is that (like amino acids) iodopyracet can behave either way.

According to the Merck Index, aqueous iodopyracet solutions have a pH ranging from 5 to 8, depending on the concentration. Iodopyracet Injection (35% (w/v)), Diodrast Concentrated Solution (70% (w/v)), and Diodrast Compound Solution (40.5% (w/v), with 9.5% (w/v) of the diethylamine as well as the diethanolamine salt) are all neutral to litmus paper.

Author: Fred Senese senese@antoine.frostburg.edu

General Chemistry Online! Is the salt of a weak acid and a weak base considered a weak acid or a weak base?