A 0.39 M solution of a weak acid is 3.0% dissociated. Calculate Ka.

1 answer

A weak acid, HA. 0.03 x 0.39 = 0.0117
................HA ==> H^+ + A^-
initial........0.39.....0....0
change.......0.0117...0.0117..0.0117
equil......0.39-0.0117.0.117..0.0117

Substitute from the ICE chart into Ka expression and solve for Ka.
Watch the significant figures.