Multiple Choice
On the pH scale, a substance with a pH of is best described as which of the following?
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17. Acid and Base Equilibrium
The pH Scale
Multiple Choice
On the pH scale at , which value is considered neutral?
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Verified step by step guidance1
Understand that the pH scale measures the acidity or basicity of a solution, ranging typically from 0 to 14 at 25\(\degree\) C.
Recall that pH is defined as the negative logarithm of the hydrogen ion concentration: \(\mathrm{pH} = -\log[\mathrm{H}^+]\).
Recognize that a neutral solution has equal concentrations of hydrogen ions \([\mathrm{H}^+]\) and hydroxide ions \([\mathrm{OH}^-]\).
At 25\(\degree\) C, the ion product of water \(K_w\) is \(1.0 \times 10^{-14}\), so \([\mathrm{H}^+] = [\mathrm{OH}^-] = 1.0 \times 10^{-7}\) M in pure water.
Calculate the pH of pure water using the formula: \(\mathrm{pH} = -\log(1.0 \times 10^{-7})\), which equals 7, indicating neutrality.
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