Table 2.

Relationships among pH, [H⁺], and R_pH

pH	[H+]	RpH
7	100	4.17
7.1	79	3.33
7.2	63	2.63
7.3	50	2.09
7.4	40	1.67
7.5	32	1.32
7.6	25	1.05
7.7	20	0.83

As pH increases, the [H⁺] and R_pH decrease in a linear and parallel fashion. With increases or decreases of 0.3 pH units, [H⁺] and R_pH are halved or doubled, respectively. Calculations are determined from the Henderson equation. [H⁺], hydrogen ion concentration (nM); R_pH, ratio of pCO₂ to [HCO₃^–] (mm Hg⋅L/mmol) (9,10,36).