Chapter 19, Problem 113A

Interpretation Introduction

Interpretation : Rapid breathing leads to abnormally high blood pH is to be explained. Slow breathing leads to abnormally low blood pH is to be explained.

Concept Introduction : The negative logarithm of the concentration of hydrogen ions is the pH of a solution. The formula to calculate pH is given as

  $\text{pH=}-{\text{log[H}}^{\text{+}}\text{]}$

Answer to Problem 113A

Rapid breathing leads to abnormally high blood pH due to a decrease of ${\text{H}}^{\text{+}}$ ions while slow breathing leads to abnormally low blood pH due to an increase of ${\text{H}}^{\text{+}}$ ions.

Explanation of Solution

The important buffer system in the blood is the hydrogen carbonate ion-carbonic buffer system.

The buffer system takes place by the following reactions:

  ${\text{H}}_{\text{2}}\text{O}\left(l\right)+{\text{CO}}_{\text{2}}\left(g\right)\rightleftharpoons {\text{H}}_{\text{2}}{\text{CO}}_{\text{3}}\left(aq\right)$

  ${\text{H}}_{\text{2}}{\text{CO}}_{\text{3}}\left(aq\right)\rightleftharpoons {\text{H}}^{\text{+}}\left(aq\right)+{\text{HCO}}_3^{-}\left(aq\right)$

There is the production of carbon dioxide by the reactions in the cell.

The excess carbon dioxide is released through the lung.

In rapid breathing, there is a large amount of carbon dioxide released.

There is the shift in equilibrium that cause the concentrations of ${\text{H}}_{\text{2}}{\text{CO}}_{\text{3}}$ and ${\text{H}}^{\text{+}}$ to decrease.

Due to the loss of ${\text{H}}^{\text{+}}$ ions, there is increase in basicity which results in basic pH.

In slow breathing, there is no release of carbon dioxide.

Due to no release of carbon dioxide, the concentrations of ${\text{H}}_{\text{2}}{\text{CO}}_{\text{3}}$ and ${\text{H}}^{\text{+}}$ increases.

Due to the higher concentration of ${\text{H}}^{\text{+}}$ ions, there is increase in acidity that results in acidic pH.