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Key Idea 3
Acidity, Basicity and the pH Scale
Concept Question: How do chemists measure the acidity or basicity of a solution? What is the pH scale

We often use the term “acidic” to describe solutions. For instance, a glass of orange juice may be acidic, but a solution of 1.0 mol L-1 hydrochloric acid is vastly more acidic. Similarly, although household ammonia is a basic solution, many caustic cleaning agents, like lye, are even more basic.

But how does chemistry explain the “acidity” or “basicity” of a solution? Are there molecular properties that define a solution as acidic or basic?