Given a weak acid HA with an initial concentration of 0.1 M and a K_a of 1.8 x 10^-5, use an ICE chart to find the equilibrium concentration of H₃O⁺.

• A. 1.80 x 10^-5 M
• B. 0.1 M
• C. 1.34 x 10^-3 M
• D. 3.00 x 10^-3 M

Answer: (C)