Question

Find pH of the solution if \([H^+] = 2 \times 10^{-4} \, \text{mol/L}\)

• A. 3.5
• B. 4.5
• C. 5.5
• D. 6.5

Hint:

For pH calculations, remember that \( \log(10^{-x}) = -x \) and \( \log(2) \approx 0.3010 \). This can help simplify calculations.

Answer 1

The Correct Option is B

The pH of a solution is given by the formula: \[ \text{pH} = -\log[H^+] \] Substitute the given value of \( [H^+] = 2 \times 10^{-4} \, \text{mol/L} \): \[ \text{pH} = -\log(2 \times 10^{-4}) \] Using logarithmic properties: \[ \text{pH} = -\log(2) - \log(10^{-4}) = -0.3010 + 4 = 4.5 \] Thus, the pH of the solution is \( 4.5 \).