Question

The PK) values for the dibasic base B are pKb1 = 2.10 and pKb2 = 7.88. Calculate the pH at each of the points in the titration of 50.0 mL of a 0.60 M B(aq) solution with 0.60 M HCl(aq). What is the pH before addition of any HCI? pH = What is the pH after addition of 25.0 mL HCI? pH = What is the pH after addition of 50.0 mL HCI? pH = What is the pH after addition of 75.0 mL HCI? pH = What is the pH after addition of 100.0 mL HCI? pH =

Answer 1

Solution : - Given tható - pkba 2010 Plba Tiration Blau) trelcao =7.68 50.0ml -0.60 Mi =0.604 pribe 011G = c'qud)"** for or 0.00794 . 3 = 7.9ue x103 7488 =10 (7.88) = 0.0000000131 1. 31x1018

(a) BHt au) tot aa) Bear) + H2O(1) bhi Bh+] Com] (B] 7. Thxto 2.44XTOS aya 0.60-a =>(0.60 -0.).(77.9441003=a? = 0.004764 - 7.94 troša = a? a + 7.94X103 a 0.0047640 => a = 0.065 M=CH-] 6.5 x 10 2 BHP (99) + Dt (99) Bir ar) + H2O (H) Kb = [BHT] [on] 1.31x108 bx (0.065+6) 0.0651b) b = 1.31x108 • fot = 0.065 n . pot = 1.20 pH = 14 -pott pH-1H-1:20 tt = 12.8

pH After addition of 25.0 M HCl: The volume of hydrochloric acid eftet) - 50 ml- x060 M2.00) o.com Ad = 30 50 ml 0.60 Volume of Hol at mid q the eaulance point = 25 ml pH = Hapkb = pka pH = 14-2010 pH = 11:9. pH After addition 50.0M Hol. pH = + (paraan & Pkaz] pt = { 18:9 + 6-te] : pH = 9.20 d pH After addition of 75-omi tich :- the rewme of hydrocloric acid (Hel) at Second Ewilance point = 2x 50 ml = 100 ml Volume of Hcl Serond Eulance - 75 ml point

. pH = the apkba = plaz =14– 751 pH = 6:49. - pH Altos addition of 1000 ml Hel chemical Reaction - BH.** (ar) + H2oC) Bu* a9) + H2ot (av) . kaz = [BH] [430t] . (But] -7 (2 3. 2xlo za 50ml x 0.60M 150 ml Con-C) 3.2x107 = (² 6.-3.2x10-78-60-64 X10165 -0. C=0.000253 M =(#3 of pt tog chizot) pH = -log (0.000953) pH = (3.59. ] 11