Question

The pH of a solution is 3. What is the concentration of \( \text{H}^+ \) ions in the solution?

• A. \( 1 \times 10^{-3} \, \text{mol/L} \)
• B. \( 3 \times 10^{-3} \, \text{mol/L} \)
• C. \( 1 \times 10^{-6} \, \text{mol/L} \)
• D. \( 3 \times 10^{-6} \, \text{mol/L} \)

Hint:

Remember: pH is the negative logarithm of the hydrogen ion concentration. A lower pH means a higher concentration of \( \text{H}^+ \) ions.

Answer 1

The Correct Option is A

Step 1: Apply the pH formula The pH of a solution is defined by the concentration of \( \text{H}^+ \) ions as:\[\text{pH} = -\log[\text{H}^+]\]Step 2: Isolate \( \text{H}^+ \) concentration To find \( [\text{H}^+] \), rearrange the formula:\[[\text{H}^+] = 10^{-\text{pH}}\]Step 3: Input the pH value With a pH of 3, substitute this into the formula:\[[\text{H}^+] = 10^{-3} = 1 \times 10^{-3} \, \text{mol/L}\]Answer: The \( \text{H}^+ \) ion concentration is \( 1 \times 10^{-3} \, \text{mol/L} \). The correct option is (1).