 Around pH 4.7 (mid-way between the first two p"K""a" values) the dihydrogen phosphate ion, , is practically the only species present.Around pH 9.8 (mid-way between the second and third p"K""a" values) the monohydrogen phosphate ion, , is the only species present.At pH 13 or higher, the acid is completely dissociated as the phosphate ion, .