Graphic representation of acid-base status

The reversible reaction of carbon dioxide with water to yield hydrogen ions and bicarbonate ions is fundamental in acid- base physiology. 

The reaction may be more complicated than this, a point taken up in the appendix to this chapter and also in Chapter 8. For the present purposes, the simple form will suffice. 

Applying the law of mass action (Chapter 1) to this equilibrium reaction, one obtains the expression 

Since in a dilute aqueous solution [H2O] is approximately constant, a new constant K is defined K = kl x [HjO] 

At body temperature, the constant K can be shown to equal 0.8 x 10. This is shown in Table 2.1 for reference. 

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