Phosphoric Acid (H₃PO₄) Has Three Dissociable Protons, with the PK_a's

question 52

Essay

Phosphoric acid (H₃PO₄) has three dissociable protons, with the pK_a's shown below. Which form of phosphoric acid predominates in a solution at pH 4? Explain your answer.
Acid
pK_a
H₃PO₄
2.14
H₂PO₄^-
6.86
HPO₄^2-
12.4

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Definitions:

Cumulative Percent

The percentage that represents the total number of cases or instances up to a certain threshold.

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Grouped Frequency Distribution

A method of displaying data by specifying the number of occurrences in each group of data.

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Continuous ranges of values or categories between two points, often used to specify confidence levels in statistics or musical distances in music.