Question

QUESTION 14 Calculate the pH at each of the following points for the titration of 50.0 mL of 0.320 M HA with 0.320 M KOH. The Ka for HA is 6.5x10-6 at 0 mL of KOH added the pH = at 15.0 mL of KOH added the pH- at 25.0 mL of KOH added the pH = at 50.0 mL of KOH added the pH = at 60.0 mL of KOH added the pH =

Answer 1

HATHO - Hot + Á 0.32 To T - x - +X X 10-32-x - x EH, ot] [A] ka EHA 6.54106 - x² 032-X For weak acid 0.32-X = 0.32 651106 = x? 6-32 x= [Hot] - 6.5X106 X0-32 = 0.00 K4221 pH=-10g 24, ot] =-109 (0-00144 22) pH = 2.841

HA: molarity = 0.32M kot molarity 20-32 M volume-soml=8-052 volume = 15m1=0.0152 M= 2 no-of moles = 0-32 X0-015 no of moles 20.32X0-05 0.0048 =0-016 HAT kolH KA THO I 0.016 16.0048 To -0.0048 -0.0048 +0.0048 Elo.012 o 10.0048 Total volume 20-05+ 0-015= 0.0652 - 0.0112 [HA] = h 22 - --0.172] 0-065 [KA3 = 0.0048 -0.07385 LIKASI 0.065 Ka= 6.58106 pka_alog ka = -log (65x100) = 5.19 {KAI pH = pka tlog E HA] pt - 5.19 tlog 0.07385 - 0-1723 4.822

kolt molarity = 0.32M volume = 25ml = 0.025 no. of moles = 0.32 x 0.025= 0.008 KATHO HAT KOH Ilo.016 10.oog -0.008 -0.008 0.008 I o - 1 +0008 10-008 total volume =0-057 0.025= 0.0752 o-008 EHATan n - =0.1067 M V 0.075 X {KA] = 0.008 Llits - 0.075 = 0.1067 M plt_pka tlog EKAI 8 ZHAT pH = 5.19 tlog 0.1067 0 :5-19

(4 kot molarity = 0.32 M volume = 50 ml = 0-052 no of moles = 032 X0-05 = 0.016 HA & KOH KA THO weak acid strong base salt I 0.06 0.016 Lo c/-o-ol6 -0.016 +0-016 E o l o 10.olo I total volume=0.05 + 0-05 = 0.12 EKAJ = 220-016 – 0.16M For this salt pH foormula pt = t [pKW + pka togel pH = 7 [1445.19 tlog (8-16)] 01 pkw_14 pH = 9.197

KOH molarity = 0.32M volume = 60ml = 0-06L no of moles = 0.32X0-08= 0.0192 HAT koH - KA THO Il 0.016 0.0192 t- (-0.016 E 1-0.016 o 10.0032 Total volume = 0.05+ 0.06 = 0.112 [koh] =2043 = 2 0.0032 = 0.02914 pOH = -log [OH-] = -10g (0.0 291) = 1.54 pt = 14-polt = 14-1.54= 12:46

pH: formula's for salt's weak acid + strong barse - salft ito pH = ± [pkw + pka + loge] strongacid & weakbase salf t pH = [ pk w pkke_loge] o