Calculate the pH of 0.010 M NH₄Cl. K _b for NH₃ is 1.8×10^{- 5}.

Question

Quizplus · Accepted Answer

The given compound is NH4Cl, which is a salt of a weak base (NH3) and a strong acid (HCl). The dissociation of NH4+ in water produces NH3 and H+. The Kb for NH3 is given indirectly through the given Ka (1.8×10^-5) for NH4+. Since Kw = Ka * Kb = 1.0×10^-14, we can find Kb = Kw / Ka = 1.0×10^-14 / 1.8×10^-5 = 5.56×10^-10. The concentration of NH4+ is 0.010 M, and using the formula for pH in such a system, pH = 14 - pOH = 14 - 0.5(pKw - log(Kb) - log([NH4+])) = 14 - 0.5(14 - log(5.56×10^-10) - log(0.010)) = 5.63.

Calculate the PH of 0