We make several buffer solutions by mixing NH₃ and NH₄Cl. Which of the following buffer solutions has the highest pH? Given that Kb(NH₃) = 1.8 x 10⁻⁵.
1) Buffer solution with equal amounts of NH₃ and NH₄Cl
2) Buffer solution with more NH₃ than NH₄Cl
3) Buffer solution with more NH₄Cl than NH₃
4) Buffer solution with only NH₃