Calculate the pH of a solution that is 0.178 M in sodium formate (NaHCO2) and in formic acid The Ka of formic acid is 1.77 × 10-4.?

HCO₂H(aq) + H₂O(l) ⇌ HCO₂⁻(aq) + H₃O⁺(aq) ...... Kₐ = 1.77 × 10⁻⁴

pH = pKₐ - log([HCO₂H]/[HCO₂⁻])
pH = -log(Kₐ) - log([HCO₂H]/[HCO₂⁻])
pH = -log(1.77 × 10⁻⁴) - log(0.178/0.178)
pH = -log(1.77 × 10⁻⁴)
pH = 3.75