Question

How many moles of NH3 are required in a 1.00L solution to create a buffer with a pH of 8.81 if the solution contains 0.64 moles of NH4Cl? Kb NH3 = 1.8 x 10-5?

Answer 1

Solution contain o.64 mol O-64-0.64(M) Molarity oNH ce in solution = 1 :. mol asgume , the 30lution lontain x CM) CLd cund we Nthen mol arity of N in solution [NMA C [NH31 Now, bOH 7 5.19= 4- 745 O-64 70.445 O.64 O.64 O445 = 2786 1 0 64 O 2290.23 a 786 mol NH2 is needed m 00 L Ecor O 23

weak bare B in H0 and it will equlibrium and form conj form Take a aeid BHt an но B (a1)20 (A) and &Ht Caq) O Ca mass-action Loo, We ГВн"] [oн] Kx LMg 0isalmost constaut as the medium is a1eour K, disso eiaton constant of base S kxM [ вн] [он] КЬ Now r61 Kx Свн] 7-o o]-o10K salt + B=Base base БОИ BHsatt pH= 4-pOH= 14-K [selt base k (NH X0 we knovo, pH+ boH= 14 poH14- as the pH of the olution - 14-8.81 5 19 8.81 volume of Nov, the olution 1 L