A 40 ml solution of weak base BOH is tritrated with 0 1M HCL pH is 10 04 and - Chemistry - Chemical and Ionic Equilibrium

Question

A 40 ml solution of weak base BOH is tritrated with 0 1M HCL pH is
10 04 and 9 14 after addition of 5 ml and 20 ml acid respectively
find out Kb for weak base

Akanksha C. · Accepted Answer

Hi,Normality of base BOH is NbasepOH = pKb + logsaltbasei ) 14-10
04 =  pKb + log5 ×0
140 × Nbase -5 ×0 1ii) 14-9
14 =  pKb + log20×0
140 × Nbase - 20 ×0
1Equating the values of pKb from above two expression, we get3
96 - log5 ×0
140 × Nbase -5 ×0 1 = 4
86-log20×0
140 × Nbase - 20 ×0
1log20×0
140 × Nbase - 20 ×0
1×5 ×0
140 × Nbase -5 ×0 1 = 0
9440 × Nbase - 5 ×0
140 × Nbase -  20 ×0
1 = 7
943On solving above equation,  Nbase = 3
47239 44= 0
088 Substitute the value of  in equation 13
96 =  pKb + log5 ×0
140 ×0 088 -5 ×0 1pKb = 3
96  - log0 166 =3 96--0 78 = 4
74Kb =1 83 ×10-5Regards

A 40 ml solution of weak base BOH is tritrated with 0.1M HCL. pH is 10.04 and 9.14 after addition of 5 ml and 20 ml acid respectively. find out Kb for weak base.