Question

Question #940b6

Answer 1

The blood's Bicarbonate weak-acid/conjugated-base buffer system.

Explanation:

Since the pH of Blood has to be maintained in the narrow range of `(7.35-7.45)`, a suitable buffer system is in order. That buffer system is the Bicarbonate Buffer System.

`CO_2` and `H_2O` are catalyzed by an enzyme called Carbonic Anhydrase to form `H_2CO_3` (Carbonic Acid) which dissociates back and forth into `HCO_3^-` (Bicarbonate) and `H^+` (Hydrogen Proton).

Here is the complete reaction:

`CO_2 + H_2O rightleftharpoons H_2CO_3 rightleftharpoons HCO_3^- + H^+`

Just like any Buffer, Bicarbonate Buffer works by neutralizing any extra acid or base introduced into the system by keeping its Weak Acid (`H_2CO_3`) and its Conjugated Base (`HCO_3^-`) in constant Equilibrium. However, just like with any buffer, if the amount of added acid or base is beyond the Buffer's Capacity, then it'll fail to balance the pH and result in cases of Acidosis or Alkalosis.

I hope that answers your question.

Further Reading:
pH
Bicarbonate Buffer System
Carbonic Anhydrase
Buffer
Weak Acid
Conjugated Base
Equilibrium
Buffer's Capacity
Acidosis
Alkalosis