Problem 4.2: The chapter says We are measuring one side of
From Chapter 4 Problem Set. Level 1: Conceptual Mastery.
Question
The chapter says “We are measuring one side of a linked equilibrium.” Explain what this means in your own words.
Answer
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pH does not describe a fixed characteristic of water. It measures where the ongoing self-ionization equilibrium currently sits: the balance between H⁺/H₃O⁺ and OH⁻ at a given moment. Adding acid or base drags that balance to a new position, and pH reports where it settled. It is a measurement of equilibrium, not a simple tally of chemical added.