Question

The pH of an aqueous solution of weak mono acidic base is 11. What is the [H\(^+\)] of the solution? [pKw = 14]

• A. \(1 \times 10^{-11}\) M
• B. \(1 \times 10^{-13}\) M
• C. \(1 \times 10^{-14}\) M
• D. \(1 \times 10^{-3}\) M
• E. \(1 \times 10^{-10}\) M

Hint:

Don't get confused by "mono acidic base".
If the question directly gives you the pH, you can always find \([H^+]\) using \(10^{-\text{pH}}\).
If you needed \([OH^-]\), you would first calculate pOH = 14 - 11 = 3.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
pH is a logarithmic scale used to specify the acidity or basicity of an aqueous solution.
By definition, pH is the negative base-10 logarithm of the hydrogen ion concentration.

Step 2: Key Formula or Approach:
The formula relating pH and hydrogen ion concentration \([H^+]\) is:
\[ \text{pH} = -\log_{10}[H^+] \]
Alternatively:
\[ [H^+] = 10^{-\text{pH}} \]

Step 3: Detailed Explanation:
Given:
pH = 11
To find the hydrogen ion concentration, substitute the pH value into the power of 10:
\[ [H^+] = 10^{-11} \text{ M} \]
Written in scientific notation:
\[ [H^+] = 1 \times 10^{-11} \text{ M} \]
Note: The information about "weak mono acidic base" and "pKw" is additional context but not strictly necessary for the calculation since the pH is already provided.

Step 4: Final Answer:
The \([H^+]\) of the solution is \(1 \times 10^{-11}\) M.