What is the Hydrogen Ion [H⁺] Concentration of a Solution

Question

What is the hydrogen ion [H⁺] concentration of a solution of pH 8?
A) 8 M
B) 8 x 10⁻⁶ M
C) 0.01 M
D) 10⁻⁸ M
E) 10⁻⁶ M

Accepted Answer

The pH scale is defined as the negative logarithm of the hydrogen ion concentration [H⁺]. Mathematically, this can be represented as pH = -log[H⁺]. Therefore, to find [H⁺], we can rearrange this equation as [H⁺] = 10⁻pH. Substituting pH = 8, we get [H⁺] = 10⁻⁸ M. Thus, the correct answer is option D.