The plot obtained on addition of
AgNO3 (aq) to solution of KCl is depicted as follows.
Ag++NO3−+K++Cl− → AgCl +
K++NO3− AgNO3(aq.)+K+Cl−(aq.) →
AgCl(s)+KNO3 On adding aqueous
AgNO3, the precipitation will not start immediately, until the ionic product of AgCl exceeds the solubility product. After that
AgNO3 will be precipitated in the form of AgCl and also at the same time
NO3− ions will be added to the solution. Since the number of ions remains the same, the conductance also remains the same (as shown by line AB in the figure). Once the precipitation is complete, on further addition of
AgNO3, the number of ions will now increase and hence the conductance will also increase (as shown by line BC).