Alkaline (basic) solutions have a pH in which of the following ranges at $25°C$?

• A. $\mathrm{pH}>14$
• B. $0\le \mathrm{pH}<7$
• C. $\mathrm{pH}=7$
• D. $7<\mathrm{pH}\le 14$

Answer: (D)

Verified step by step guidance

1. Recall that pH is a measure of the hydrogen ion concentration in a solution, defined as \(\mathrm{pH} = -\log[\mathrm{H}^+]\).
2. Understand the pH scale ranges from 0 to 14 at 25\(\degree\) C, where pH 7 is neutral, values less than 7 are acidic, and values greater than 7 are basic (alkaline).
3. Identify that an alkaline (basic) solution has a lower concentration of hydrogen ions than pure water, so its pH must be greater than 7.
4. Recognize that the maximum pH value on the scale is 14, which corresponds to the lowest hydrogen ion concentration in aqueous solutions at 25\(\degree\) C.
5. Conclude that the pH range for alkaline solutions at 25\(\degree\) C is \(7 < \mathrm{pH} \leq 14\).