What is the pH of a solution with a 3.8 * 10-4 M hydronium ion concentration?

3.4

Explanation:

The pH scale is used to express the acidity or basicity of a solution.

If the pH <7, the solution is acid. If the the solution is neutral. If the pH> 7, the solution is basic.

Given the hydronium ion concentration [H₃O⁺] = 3.8 * 10⁻⁴ M, we can calculate the pH using the following expression.

pH = - log [H₃O⁺]

pH = - log 3.8 * 10⁻⁴

pH = 3.4

This solution is acid.