Question

What is the pH of a solution when the concentration of hydrogen ions \([H^+]\) is \( 1 \times 10^{-5} \, \text{mol/L} \)?

• A. 5
• B. 9
• C. 7
• D. 4

Hint:

The pH is the negative logarithm of the hydrogen ion concentration. A pH of 7 is neutral.

Answer 1

The Correct Option is A

The pH of a solution is given by the formula: \[ \text{pH} = -\log [H^+] \] We are given that the concentration of hydrogen ions is \( [H^+] = 1 \times 10^{-5} \, \text{mol/L} \). Now, calculate the pH: \[ \text{pH} = -\log (1 \times 10^{-5}) = 5 \] Therefore, the pH of the solution is 5, which corresponds to option (1).