Determination of the hydrolysis constant by conductance measurement

3- Determination of the hydrolysis constant by conductance measurement:
Anilinium chloride C6H5NH3Cl (salt of weak base C6H5NH2 aniline and strong acid HCl).




C = eq. concentration of the salt
?c = the concentration of & HCl (as )
= the concentration of unhydrolysis salt ( ).
= degree of hydrolysis

?s=(1-?)?c+??a+??b
?s = eq. conductance of salt solution
?c = eq. conductance of the unhydrolysis salt
?a = eq. conductance of the acid
?b = eq. conductance of the base
?b : is very small comparison to ?a + ?c, so we can neglected.
?s=(1-?)?c+??a
Suppose a solution of HCl is to be titrated against NaOH solution. for this purpose the HCl solution is taken in a beaker and the NaOH solution in the burette.
The conductance of the acid solution is noted initially as well as after successive addition of small amount of NaOH solution.
Evidently, the conductance of the acid solution in the beginning is very high because it contains highly mobile H+ ions (HCl ? H+ + Cl-).


?c = obtained from measured ? that dissolved in aniline ( )
? (kholrausch’s law)
So, from we can measured :

4-Conductometric Titration :
Conductance measurement may be employed to determine the end points of various titrations:
1- conductometric titration of strong acid with a strong base: