A solutionof weakbase BOHwas titrated with 0.1 N HCl . The pHof the solution was foundto be10.24and 9.14 after the additionof 5 ml and20ml of the acidrespectively. Findthe dissociation constantof the base .

A solutionof weakbase BOHwas titrated with 0.1 N HCl . The pHof the so

1.	A solutionof weakbase BOHwas titrated with 0.1 N HCl . The pHof the solution was foundto be10.24and 9.14 after the additionof 5 ml and20ml of the acidrespectively. Findthe dissociation constantof the base .
Answer» SOLUTION :`{:("Case-I",BOH,+,HCl,to,BCl,+,H_(2)O),("Millimole before reaction",a,,0.1 xx5 = 0.5,,0,,0),("millimole after reaction ",(a-0.5),,0,,0.5,,0.5):}` ` :. pOH= - log K_(b) + log. ([BCl])/([BOH])""` …..(i) ` :.pH = 10.04` ` :.3.96 = - logK_(b) + log. (0.5)/((a-0.5))""` ....(ii) ` :. pOH= 3.96 ` Case - II :`BOH + HClto BCl +H_(2)O ` ` {:("Millimole before reaction ",a,0.1xx20=2,,),("Millimole after reaction ",(a-2),0,2,2):}` ` :. pOH = - log K_(b) + log. ([BCl])/([BOH])""` ...(III) ` :.pH = 9.14 :. pOH = 4.86 ` ` :. 4.86= - log K_(b) + log . 2/((a-2))""` ....(iv) Solving Eqs.(ii) and (iv) , `K_(h) = 1.81 xx10^(-5)`