# Question #c74c8

May 17, 2014

The hydrogen ion concentration of a pH 3.5 solution is 3.2 × 10⁻⁴ mol/L

The definition of pH is

pH = -log[H₃O⁺], so

-log[H₃O⁺] = 3.5 or

log [H₃O⁺] = -3.5

To calculate [H₃O⁺], we take the antilogarithm of both sides of the equation (the ${10}^{x}$ key on your calculator).

[H₃O⁺] = ${10}^{-} 3.5$ mol/L = 3.2 × 10⁻⁴ mol/L