The pH of the ocean is 8.1. What is the concentration of hydronium ions?

7.9 × 10⁻⁹ M

Explanation:

Step 1: Given data

pH of the ocean: 8.1

Step 2: Calculate the concentration of hydronium ions

We will use the definition of pH.

pH = -log [H⁺] = -log [H₃O⁺]

[H₃O⁺] = [H⁺] = antilog -pH

[H₃O⁺] = antilog -8.1 = 7.9 × 10⁻⁹ M

Since [H₃O⁺] < 10⁻⁷ M, the solution is basic.