Phosphoric acid is polyprotic, with
p_(a)^(')
s of
2.14,6.86
, and 12.4 . The ionic form that predominates at
pH
3.2 is: a.
HPO_(4)^(2-)
b.
PO_(4)^(3-)
c.
H_(2)PO_(4)^(-)
d.
H_(3)PO_(4)
