Human blood contains a buffer of carbonic acid and bicarbonate anion...?
Human blood contains a buffer of carbonic acid and bicarbonate anion. In this buffer, hydronium cation and bicarbonate anion are in equilibrium with carbonic acid. The concentration in blood is approximately 24mM.
You are asked to make one liter of a 0.5M stock solution of this buffer at pH 7.4 with sodium bicarbonate (the salt) and 1.0M HCl. The pKa of H2CO3 is 6.35
As silly as it sounds, I'm having trouble figuring out how to make the equation to even begin this. How do I relate the buffer solution back to the stock solution I'm supposed to make?
- Bobby_ThinLv 71 month agoFavourite answer
H2CO3 + H2O =HCO3 - + H3O+
When any acidic substance enters the bloodstream, the bicarbonate ions neutralize the hydronium ions forming carbonic acid and water. Carbonic acid is already a component of the buffering system of blood. Thus hydronium ions are removed, preventing the pH of blood from becoming acidic.
On the other hand, when a basic substance enters the bloodstream, carbonic acid reacts with the hydroxide ions producing bicarbonate ions and water. Bicarbonate ions are already a component of the buffer. In this manner, the hydroxide ions are removed from blood, preventing the pH of blood from becoming basic.
pKa = pH * log [A-]/[HA]