Which of the following best describes a solution with a neutral pH?

• A. It has a pH of 7 and equal concentrations of H^+ and OH^- ions.
• B. It has a pH of 0 and contains only H^+ ions.
• C. It has a pH less than 7 and more H^+ ions than OH^- ions.
• D. It has a pH greater than 7 and more OH^- ions than H^+ ions.

Answer: (A)

Verified step by step guidance

1. Understand that pH is a measure of the hydrogen ion concentration in a solution, defined by the formula \(\mathrm{pH} = -\log[\mathrm{H}^+]\).
2. Recognize that a neutral solution means it is neither acidic nor basic, which implies the concentrations of hydrogen ions (\(\mathrm{H}^+\)) and hydroxide ions (\(\mathrm{OH}^-\)) are equal.
3. Recall that in pure water at 25°C, the concentration of \(\mathrm{H}^+\) ions is \$1 \times 10^{-7}\( M, and the concentration of \)\mathrm{OH}^-\( ions is also \)1 \times 10^{-7}$ M, making the solution neutral.
4. Since \(\mathrm{pH} = -\log[\mathrm{H}^+]\), substituting \([\mathrm{H}^+] = 1 \times 10^{-7}\) M gives a pH of 7 for a neutral solution.
5. Therefore, a solution with a neutral pH has a pH of 7 and equal concentrations of \(\mathrm{H}^+\) and \(\mathrm{OH}^-\) ions.