Question

What is the pH of a 0.01 M solution of HCl?

• A. 1
• B. 2
• C. 3
• D. 4

Hint:

For strong acids, pH is calculated directly from the molar concentration using \( \text{pH} = -\log_{10} [\text{H}^+] \).

Answer 1

The Correct Option is B

Step 1: HCl is a strong acid, so it dissociates completely: \( [\text{H}^+] = 0.01 \, \text{M} \).
Step 2: Calculate pH using the formula: \[ \text{pH} = -\log_{10} [\text{H}^+] \] \[ [\text{H}^+] = 0.01 = 10^{-2} \] \[ \text{pH} = -\log_{10} (10^{-2}) = 2 \] Step 3: Verify: For a strong acid, pH depends only on concentration. Matches option (2).