According to the Henderson-Hasselbalch equation:
$$\text{pH} = \text{pK}_a + \log\left(\frac{[\text{HCO}_3^-]}{[\text{H}_2\text{CO}_3]}\right)$$For the bicarbonate buffer system at physiological conditions, $\text{pK}_a = 6.1$. To maintain blood plasma pH at 7.4:
$$7.4 = 6.1 + \log\left(\frac{[\text{HCO}_3^-]}{[\text{H}_2\text{CO}_3]}\right)$$ $$\log\left(\frac{[\text{HCO}_3^-]}{[\text{H}_2\text{CO}_3]}\right) = 7.4 - 6.1 = 1.3$$ $$\frac{[\text{HCO}_3^-]}{[\text{H}_2\text{CO}_3]} = 10^{1.3} \approx 20:1$$हेंडरसन-हैसलबैक समीकरण (Henderson-Hasselbalch equation) के अनुसार:
$$\text{pH} = \text{pK}_a + \log\left(\frac{[\text{HCO}_3^-]}{[\text{H}_2\text{CO}_3]}\right)$$शारीरिक तापमान पर कार्बोनिक अम्ल का $\text{pK}_a = 6.1$ होता है। प्लाज्मा के सामान्य $\text{pH} = 7.4$ के लिए:
$$7.4 - 6.1 = 1.3 = \log(20)$$