Bicarbonate Ion

[qw098]

Hi:

Is the Bicarbonate Ion that is released in the small intestine via hormone secretion; is it considered a base or an acid!?

Thanks!

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[Singhp03]

Hi:

Is the Bicarbonate Ion that is released in the small intestine via hormone secretion; is it considered a base or an acid!?

Thanks!

base, interaction with chyme(acidic), net result: increase in pH

However, if it was interacting with another base, it would act as proton donating and thus as an Acid.

 

[indianjatt]

It acts as a base to neutralize the chyme that enters the duodenum from the stomach via the pyloric sphincter . And it's excreted by the effects of the exocrine hormone secretin

 

[imbackasd]

how did you know that? which review book goes over this concept ?

 

[indianjatt]

I learned it from my physiology class.

 

[NonTraditional3]

bicarbonate is amphoteric. Sodium Bicarbonate is purely a base, while Carbonic Acid is amphoteric, after dissociation of the first hydrogen ion, to act as an acid, HCO3- would need to be reacting with a compound with a higher pka. To act as a base, it must react with something that has a lower pka.

 

[V5RED]

bicarbonate is amphoteric. Sodium Bicarbonate is purely a base, while Carbonic Acid is amphoteric, after dissociation of the first hydrogen ion, to act as an acid, HCO3- would need to be reacting with a compound with a higher pka. To act as a base, it must react with something that has a lower pka.

Bicarbonate(HCO3-) is amphoteric.
Sodium bicarbonate(NaHCO3) IS bicarbonate. Bicarbonate is an anion. The sodium is the cation to which it is bound in those pretty little vials in which bicarbonate is stored. Once you add it to water you get bicarbonate(HCO3-) and the spectator ion sodium (Na+) Thus sodium bicarbonate is amphoteric.
Carbonic acid is NOT amphoteric. H2CO3 will not gain protons. There is no such thing as H3CO3.

how did you know that? which review book goes over this concept ?

I know that EK and TBR go over it. I assume that all review books would.

 

[JaBoomDay]

It acts as a base to neutralize the chyme that enters the duodenum from the stomach via the pyloric sphincter . And it's excreted by the effects of the exocrine hormone secretin

Just a small correction on this, secretin is not an exocrine hormone. It's an endocrine hormone.
Exocrine - substance is released outside of the body or into a duct.
Endocrine - substance is released directly into the blood stream.

Secretin is released into the blood stream and then stimulates the parietal cells in the stomach to release HCl. The presence of acidified chyme in the duodenum is what stimulates the release of bicarbonate from the pancreas to neutralize.