Question

What is the pH of a 0.01 M solution of hydrochloric acid (HCl)?

• A. 12
• B. 2
• C. 7
• D. 1

Hint:

For strong acids, the concentration of \( \text{H}^+ \) ions is equal to the concentration of the acid.

Answer 1

The Correct Option is B

Hydrochloric acid (HCl) is a strong acid, meaning it dissociates completely in water. The concentration of \( \text{H}^+ \) ions is the same as the concentration of the acid, which is 0.01 M. The pH is calculated using the formula: \[ \text{pH} = -\log [\text{H}^+] \] Substitute \( [\text{H}^+] = 0.01 \) M: \[ \text{pH} = -\log (0.01) = 2 \] Thus, the pH of the solution is 2, corresponding to option (2).