for the dissociation equilibrium of formic acid

Question

For the dissociation equilibrium of formic acid, HCO₂H(aq) ↔ H⁺(aq) + HCO₂^- (aq), the acid dissociation constant at 298.15K has the value K_a = 1.77 *10^-4.

(a) Find the degree of dissociation and the hydrogen ion molality in a 0.01000 molal formic acid solution. You can safely set Γ_r and γ_m,HA equal to 1, and use the Debye-Huckel limiting law to calculate γ+. You can do this calculation by iteration: Start with an initial estimate of the ionic strength (in this case 0), calculate γ+ and, α and repeat these steps until the value of α no longer changes.

(b) Estimate the degree of dissociation of formic acid in a solution that is 0.01000 molal in both formic acid and sodium nitrate, again using the Debye-Huckel limiting law for γ+. Compare with the value in part (a).