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Q1)Diethylamine, (C2H5)2NH, is a weak base (pKb=3.16 at 25oC). What is the pH of

ID: 746978 • Letter: Q

Question

Q1)Diethylamine, (C2H5)2NH, is a weak base (pKb=3.16 at 25oC). What is the pH of 0.155 mol/L (C2H5)2NH(aq) at 25oC? Give your answer accurate to two decimal places. Q2)Which of the following expressions hold for 0.10 mol/L Na2HA(aq). (HA2- is the doubly-ionized form of H3A, a weak triprotic acid.) A) [H2A-] = 2 [HA2-] = 3 [A3-] B)0.5 [Na+] = [H3A] + [H2A-] + [HA2-]+[A3-] C) [H+] = [H2A-] + 2 [HA2-] + 3 [A3-] + [OH-] D)[H+] = [H2A-] + [HA2-] + [A3-] + [OH-] E) Ka1=[H2A-][H+]/[H3A] F)Ka2=Kw/Ka1 G)[H+] + [OH-] = Kw

Explanation / Answer

F)Ka2=Kw/Ka1 G)[H+] + [OH-] = Kw