Question

If `K_(a_(1)),K_(a_(2))` are the first, second and third ionization constants of `H_(2)PO_(4)` respectively and `K_(a_(1)) gtgt K_(a_(2)) gtgt K_(a_(3))`. Which is/are correct:
A. `[H^(+)] = sqrt(k_(a_(1))[H_(3)PO_(4)])`
B. `[H^(+)] = [HPO_(4)^(2-)]`
C. `K_(a_(2)) = [HPO_(4)^(2-)]`
D. `K_(a_(1)) = [HPO_(4)^(2-)]`

Answer 1

Correct Answer - A::C
In case of polyprotic acids, divalent anion concentration is equal to `K_(a_(2))`