Ions of Water

Part of the Acids and Bases section of Coddy's Chemistry journey. Lesson 11 of 30.

At 25 °C, in any water solution:

$[\mathrm{H_3O^+}][\mathrm{OH^-}] = 1.0 \times 10^{-14}$

Pure water: [H₃O⁺] = [OH⁻] = 1.0 × 10⁻⁷ M.

More H₃O⁺ means less OH⁻, and the other way round. One gives the other: [OH⁻] = 10⁻¹⁴ / [H₃O⁺].

Challenge

A sample of rainwater has [H₃O⁺] = $1.0 \times 10^{-3}\ \mathrm{M}$ . What is [OH⁻] in it?

Try it yourself

Acids and basesWork out the solution

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Acids and Bases

1Acids and Bases

4Neutralization

2Strong and Weak

5Acids Around Us

3The pH Scale

6Practice Problems