Given a weak acid HA with an initial concentration of 0.05 M and a K_a of 2.5 x 10^-5, use an ICE chart to find the equilibrium concentration of A^-.

• A. 1.12 x 10^-3 M
• B. 2.24 x 10^-3 M
• C. 0.05 M
• D. 2.5 x 10^-5 M

Answer: (A)