Multiple Choice
At 25 °C, what is the pH of pure distilled water?
32
views
17. Acid and Base Equilibrium
The pH Scale
Multiple Choice
On the pH scale, pH is defined as . What concentration does pH measure?
A
The concentration of hydrogen ions,
B
The concentration of undissociated water molecules,
C
The concentration of the conjugate base of the acid present in solution
D
The concentration of hydroxide ions,
Verified step by step guidance1
Understand that pH is a measure of the acidity of a solution, which relates to the concentration of hydrogen ions (H\(\textsuperscript{+}\)) present.
Recall the definition of pH: \(\mathrm{pH} = -\log_{10} \left( [\mathrm{H}^+] \right)\), where \([\mathrm{H}^+]\) represents the molar concentration of hydrogen ions in the solution.
Recognize that the logarithm function in the pH formula converts the hydrogen ion concentration into a more manageable scale, where lower pH values correspond to higher hydrogen ion concentrations (more acidic), and higher pH values correspond to lower hydrogen ion concentrations (more basic).
Note that pH does not measure the concentration of undissociated water molecules (\([\mathrm{H_2O}]\)), the conjugate base of the acid, or hydroxide ions (\([\mathrm{OH}^-]\)) directly, although these species are related through equilibrium in aqueous solutions.
Conclude that the pH specifically measures the concentration of hydrogen ions (\([\mathrm{H}^+]\)) in the solution.
Related Videos
Related Practice
