A student dissolves 0.0600 mol of a strong monoprotic acid HA in enough water to make 300.0 mL of solution. What is the pH of the resulting solution? Assume complete dissociation.
Show the answer and explanation
Correct answer
A. 0.70
Principle or equation
For a strong monoprotic acid, complete dissociation gives [H+] = initial concentration of the acid. pH = -log10[H+]. Concentration is moles per liter.
Why this answer is correct
Calculate molarity: 0.0600 mol / 0.300 L = 0.200 M. Since it is a strong monoprotic acid, [H+] = 0.200 M. pH = -log(0.200) = 0.699, approximately 0.70.
Example
If 0.0100 mol of HCl is dissolved in 100.0 mL, molarity = 0.100 M, pH = 1.00.
This published item includes a stored explanation and passed the platform’s publication workflow. It is independent preparation material, not a claim of an official or recalled examination question.