posted by Anonymous .
A 8.6 x 10^-3M solution of H3PO4 has a pH=2.30. What is Ka for H3PO4
H3PO4 has three ionization constants, k1, k2, and k3. Probably you mean to calculate k1.
H3PO4 ==> H^+ + H2PO4^-2
k1 = (H^+)(H2PO4^-2)/(H3PO4)
Convert pH = 2.30 to (H^+). Assume (H2PO4^-2) is the same (almost true). Prepare an ICE chart, substitute and calculate k1. Post your work if you get stuck.
Ka = 1.8 X 10-4