Multiple Choice
The pH scale is a logarithmic measure of which ion concentration in aqueous solution?
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17. Acid and Base Equilibrium
The pH Scale
Multiple Choice
On the pH scale at , what is the pH of a neutral aqueous solution?
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Verified step by step guidance1
Understand that pH is a measure of the hydrogen ion concentration in a solution, defined as \(\mathrm{pH} = -\log[\mathrm{H}^+]\).
Recognize that a neutral aqueous solution means the concentration of hydrogen ions \([\mathrm{H}^+]\) equals the concentration of hydroxide ions \([\mathrm{OH}^-]\).
At 25\(\degree\) C, the ion product constant for water \(K_w\) is \(1.0 \times 10^{-14}\), where \(K_w = [\mathrm{H}^+][\mathrm{OH}^-]\).
Since the solution is neutral, \([\mathrm{H}^+] = [\mathrm{OH}^-]\), so \([\mathrm{H}^+]^2 = K_w\); solve for \([\mathrm{H}^+]\) by taking the square root: \([\mathrm{H}^+] = \sqrt{K_w}\).
Calculate the pH by substituting \([\mathrm{H}^+]\) into the pH formula: \(\mathrm{pH} = -\log[\mathrm{H}^+]\).
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