Problem 5.4: A cooling tower operator stops feeding acid No

From Chapter 5 Problem Set. Level 1: Conceptual Mastery.

Question

A cooling tower operator stops feeding acid. No chemicals are added, yet the pH rises from 7.5 to 8.8. Explain why, using the concepts of CO₂ stripping and equilibrium shift.

Answer

Show answer

The tower continuously strips CO₂ from the water through warm temperature, massive airflow, and enormous surface area. As CO₂ leaves, equilibrium shifts to replace it: carbonic acid decomposes, bicarbonate consumes H⁺. The decrease in hydrogen increases the pH.