Chapter 10.8, Problem 10.60PP

Interpretation Introduction

To determine: Why the pH of blood plasma decreases on holding breath.

Solution: When we hold our breath, we exhale less (or no) carbon dioxide (CO₂) than usual. This increases the carbon dioxide (CO₂) concentration in the blood. As a result, the bicarbonate/carbonic acid equilibrium shifts to the right. The corresponding increase in [H₃O⁺] results in the decrease of the pH of blood plasma.

$2H_{2}O(l)+C{O}_2(aq)\stackrel{}{\rightleftharpoons }{H}_{2}C{O}_3(aq)+H_{2}O(l)\stackrel{}{\rightleftharpoons }{H}_3{O}^{+}(aq)+HC{O}_3{}^{-}(aq)$

Given: pH of blood plasma decreases when we hold our breath