What is the pH of a solution with a hydrogen ion concentration of 1 x 10^-3 M?

To determine the pH of a solution based on its hydrogen ion concentration, the formula pH = -log[H⁺] is used, where [H⁺] represents the concentration of hydrogen ions in moles per liter (M).

In this case, the hydrogen ion concentration is given as 1 x 10^-3 M. Plugging this value into the pH formula, we have:

pH = -log(1 x 10^-3)

Calculating this gives:

pH = -(-3) = 3.

Therefore, the pH of the solution is indeed 3. This indicates a slightly acidic solution, as a pH of 7 is neutral, values lower than 7 represent acidic solutions, and values higher than 7 represent basic solutions. In the context of the other choices, which include a neutral pH of 7 and higher pH values, a pH of 3 clearly denotes that the concentration of hydrogen ions is significant enough to place the solution in the acidic range, confirming that the chosen answer is appropriate.