Question

The dibasic compound B (pKb1 5 4.00, pKb2 5 8.00) was titrated with 1.00 M HCl. The initial solution of B was 0.100 M and had a volume of 100.0 mL. Find the pH at the following volumes of acid added and make a graph of pH versus Va: Va 5 0, 1, 5, 9, 10, 11, 15, 19, 20, and 22 mL.

pKb1= 4.00

pkb2= 8.00

11-23. The dibasic compound B (pKb1 = 4.00, pKb2 = 8.00) was titrated with 1.00 M HCl. The initial solution of B was 0.100 M and had a volume of 100.0 mL. Find the pH at the following volumes of acid added and make a graph of pH versus Va: Va = 0, 1, 5, 9, 10, 11, 15, 19, 20, and 22 mL.

Answer 1

Sol: Given daia. The dibaste Compaund B PKbi4.00 Was titoated th PKba 8.00 0. loo and 0f B Solution The was intial had Of loo.o mL a volume B +H20 BH Ho PKb4, Pkal 1o BHHo BH2 o + Pk ba 8 Pkaa6 producef The first neutsali3ation Cep is a volume When /1.000M V= 100 mL x o.100 M .O00 M is added lo mL lc CENS Preduced Second The neutsaligation when volume ts added lo mL a aomL icl

The intial p 440Cb,xcbase po 0.5pkb0.5 lo3 CB 2+0.5 3.5 14 a.5 1.5 Solutions added the For 1,5 and 9 mLHc Con-tains the buffes BBtt f pkalt log/B Foomala CCen VolHc addeof ph lo.95 (1039 0.95 10+ (03 9 A mL 10 t log 5/5 5 mL to.00 9.05 tot A FPI (10 m Hcl added) The Solution ontains the Species amphotere P CPKal tPkaa Co+) added he For el Solutton 1, 5, and BHT B2f the buffer Comtains PH-PkaCBu/CB fosmula

Vel H addedB/ CB42) PH 11 ml 6.95 5/5 15 mL 6. oo G0g (9mL 5.05 O Solution At Epa Ca0mL He added the Con centsation Contains the acid BH and ts O083M O-1o 0 X too mL 180 mL s dluted -to o5 pkaa- -3+ 0-54 -3.54 For aa mL added Sol4tion of YOu have the Hcl Cxcess The Excess b amt cl that Contain O.00a L X O.00 a mol tHcl The inal vo lame Of Solution is o o aa =12a mL The in Excess is Concentiation Of Hc o.1aaL O.o164 6.o0amol P O. o164 l8

pht the to Cse the Oesu1ts acidl pt vs Vadded Vadded acid pt 1.5 O mL 11 mL 5 mL 9mL lo mL 11 mL 15 mL (9 mL 3.5 20 mL 1.8 93 mL