Question

What effect does rapid exhalation of CO2 during exercise have on the concentration of H2CO3 in the blood?

Answer 1

You should be aware of the bicarbonate buffer equilibrium that exists in the blood. Specifically:

\[H^+ + HCO_3^- \leftarrow \rightarrow H_2CO_3 \leftarrow \rightarrow H_2O+CO_2\]
If you start rapidly exhaling CO2, the equilibrium will shift to the right in the reaction above, meaning the concentration of H2CO3 will decrease.