Question

The pOH of 0.01 M HCl solution is ________.

• A. 1
• B. 2
• C. 11
• D. 12

Hint:

Don't confuse pH and pOH. For acids, first find the pH from $[H^+]$, then subtract from 14 to get pOH.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
HCl is a strong acid that dissociates completely in water.
\[ HCl \rightarrow H^+ + Cl^- \]
The concentration of $H^+$ ions is equal to the concentration of the acid for a monoprotic strong acid.
Step 2: Key Formula or Approach:
1. \( pH = -\log[H^+] \)
2. \( pH + pOH = 14 \) (at 298 K)
Step 3: Detailed Explanation:
Given: \( [HCl] = 0.01 \text{ M} = 10^{-2} \text{ M} \)
Therefore, \( [H^+] = 10^{-2} \text{ M} \).
Calculate pH:
\[ pH = -\log(10^{-2}) = 2 \]
Calculate pOH:
\[ pOH = 14 - pH \]
\[ pOH = 14 - 2 = 12 \]
Step 4: Final Answer:
The pOH of the solution is 12.