A galvanic cell is based on the following half-reactions:
Fe²⁺ +2e⁻ ⟶ Fe(s) ⁰ = -0.440 V
2H⁺ +2 e⁻ ⟶ H₂(g) ⁰ = 0.000 V
Where the iron compartment contains an iron electrode and [Fe²⁺]= 1.00 x 10⁻³ M and the hydrogen compartment contains a platinum electrode, P_H₂ =1.00 atm, and a weak acid, HA, at an initial concentration of 1.00 M. If the observed cell potential is 0.333 V at 25 ⁰C, calculate the Kₐ value for the weak acid HA .