On the pH scale, which value represents a neutral solution at 25°C?

• A. pH = 1
• B. pH = 7
• C. pH = 14
• D. pH = 0

Answer: (B)

Verified step by step guidance

1. Understand that the pH scale measures the acidity or basicity of a solution, ranging typically from 0 to 14 at 25°C.
2. Recall that pH is defined as \(\mathrm{pH} = -\log[\mathrm{H}^+]\), where \([\mathrm{H}^+]\) is the concentration of hydrogen ions in moles per liter.
3. Recognize that a neutral solution has equal concentrations of hydrogen ions \([\mathrm{H}^+]\) and hydroxide ions \([\mathrm{OH}^-]\), which occurs when \([\mathrm{H}^+] = 1 \times 10^{-7}\) M at 25°C.
4. Calculate the pH of a neutral solution by substituting \([\mathrm{H}^+] = 1 \times 10^{-7}\) M into the pH formula: \(\mathrm{pH} = -\log(1 \times 10^{-7})\).
5. Conclude that the pH value corresponding to a neutral solution at 25°C is 7.