Arsenic acid, H3AsO4(aq), is a weak polyprotic acid that is highly toxic. It is
used as a wood preservative, a biocide and a reagent in the synthesis of
some dyes. Arsenic acid reacts with water, as represented by the following
Bronsted-Lowry equations.

A.
H3AsO4(aq) + H2O(1) = H2AsO4(aq) + H3O+(aq)
B.
H2AsO4(aq) + H2O(l) = HASO(aq) + H3O+ (aq)
C.
HASO(aq)+H2O(l) = AsO4-(aq)+H3O+(aq)

Match the following K, values with the above equilibriums.
1. 5.6 x 10-3
2. 4.0 x 10-12
3. 1.7 x 10-7