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: Use the formula for pH The pH of a solution is related to the concentration of \( \text{H}^+ \) ions by the formula: \[ \text{pH} = -\log[\text{H}^+] \] Step 2: Rearrange the formula to find the concentration of \( \text{H}^+ \) Rearranging the formula to solve for \( [\text{H}^+] \): \[ [\text{H}^+] = 10^{-\text{pH}} \] Step 3: Substitute the given pH value Given that the pH is 3, substitute this value into the formula: \[ [\text{H}^+] = 10^{-3} = 1 \times 10^{-3} \, \text{mol/L} \] Answer: Therefore, the concentration of \( \text{H}^+ \) ions is \( 1 \times 10^{-3} \, \text{mol/L} \). So, the correct answer is option (1).