Answer:
pH = 5.58
Explanation:
Given that :
Citric acid is a triprotic acid with the formula [tex]H_3C_6H_5O_7[/tex] . Tripotic acids are acids that have the tendency to yield three protons per molecule during the phases of dissociation, therefore they have three pka.
For Citric acid; the pka values are:
[tex]pKa _1 = 3.13\\pKa_2 = 4.76\\pKa_3 = 6.40[/tex]
So, the pH of sodiummonohydrogencitrate with the chemical formula [tex]Na_2HC_6H_5O_7[/tex] which can act as an acid and a base (i.e it is said to be amphoteric) can be calculated as :
[tex]pH = \frac{pKa_2+pKa_3}{2}[/tex]
[tex]pH = \frac{4.76+6.40}{2}[/tex]
pH = 5.58
Therefore, the approximate pH of a solution of sodium monohydrogencitrate = 5.58
