What is the equilibrium constant for a weak acid HA that dissociates 1% at an initial concentration of 0.05 M according to the following balanced chemical equation?
HA <----> H+ + A-
........HA <----> H+ + A-
I.....0.05........0.....0
C....-5E-5........5E-5..5E-5
E......?..........5E-5..5E-5
Substitute the E line (after evaluation 0.05-5E-5) and solve for Ka.