# Conductometric titration curve when KCl is gradually added to AgCl solution [closed]

The situation given is that we are performing conductometric titration where KCl is gradually added to AgCl solution and we have to plot the variation of conductivity with the volume of aq. KCl added. I am new to conductometric titration and I have covered the cases of titration of acid v/s bases but I have never come across a case like this.

My thought was that since AgCl is a weak electrolyte it's initial conductivity would be low. And now we add KCl to it which is a strong electrolyte so the conductivity should increase. I also think that common ion effect would come into play and the dissociation of AgCl would be pushed back further but I'm still unsure about how an end point would be obtained here. Can someone guide me? Any help would be appreciated.

• Please provide more details about the experiment. We can't guess what experiment you are doing.
– MaxW
Apr 5, 2020 at 17:53
• It isn't an experiment. It's an MCQ question I was solving in my course material. Apr 5, 2020 at 18:42
• Could we have the problem exactly as stated? I think I know what is happening, but I'm somewhat confused by the phrase "AgCl solution."
– MaxW
Apr 5, 2020 at 18:43
• I think the OP means AgNO3. Nobody can titrate KCl with AgCl. OP check your experimental notebook. Apr 5, 2020 at 19:04
• @M.Farooq No it's given as AgCl with KCl, could be a typo. I already know the AgNO3 experiment. Apr 5, 2020 at 19:40

I'm a bit puzzled by the phrase "AgCl solution," since there wouldn't be a solution but rather colloidal size particles of AgCl in the aqueous solution. I don't think you could have a bottle of colloidal size particles of AgCl since once dried the particles would stick together in a lump.

For AgCl, a tiny amount would dissolve hence there would be conductivity slightly better than pure water.

$$\ce{AgCl(s) <=> Ag+(aq) + Cl-(aq)}$$

However AgCl also form a complex with chloride:

$$\ce{AgCl(s) + Cl-(aq) <=> AgCl2-(aq)}$$

So as you add KCl the curve would show one slope as KCl builds up enough concentration to dissolve the AgCl dissolves, then a second slope as the AgCl dissolves, then a third slope after all the AgCl has dissolved.

For ecah change the curve won't look like two straight lines intersecting at a point but more like a parabola. So you'd need to extend linear portion of each and find the end point at the intersection of the linear extensions.

• This is beyond the high school level. It is very likely a typo. It must be AgNO3. The whole experiment is described here: ausetute.com.au/conductpptn.html. It is a simple curve. Apr 5, 2020 at 19:09
• @M.Farooq - Super fantastic! Yes, a $\ce{AgNO3}$ solution would make much more sense.
– MaxW
Apr 5, 2020 at 19:15
• @MaxW Your answer is correct. The graph shown in the answer is just as you described. Apr 5, 2020 at 19:41
• @infinite-blank-would you mind sharing the picture of the curve? Apr 5, 2020 at 22:03

While yes, for AgCl, a small amount could dissolve per the reactions

$$\ce{AgCl(s) <=> Ag+(aq)+Cl−(aq)}$$

$$\ce{AgCl(s) + Cl−(aq) <=> AgCl2−(aq)}$$

However, I believe the presence of the AgCl as a suspension would have an impact on conductivity per this source, as well, where AgCl particles replace Al2O3–H2O per the abstract below:

In this study, Al2O3–H2O nanofluids were synthesized using sodium dodecylbenzenesulfonate (SDBS) dispersant agent by ultra-sonication method. Different amounts of SDBS i.e. 0.1, 0.2, 0.3, 0.6, 1 and 1.5 wt.% were tested to stabilize the prepared nanofluids. The stability of nanofluids was verified using optical microscope, transmission electron microscope and Zeta potential. After selecting the suitable amount of dispersant, nanofluids with different volume fractions of Al2O3 were prepared. Zeta potential measurement of nanofluids with low alumina and intermediate fractions showed good dispersion of Al2O3 nanoparticles in water, but nanofluids with high mass fraction were easier to aggregate. The stabilized nanofluids were subjected for measuring of rheological behavior and electrical conductivity. The electrical conductivity was correlated to the thermal conductivity according to Wiedemann–Franz law. The results revealed that the nanofluid containing 1% SDBS was the most stable one and settling was observed for the fluid contained 0.75 vol.% of Al2O3 nanoparticles which gave higher viscosity. The rheological measurements indicated that the viscosity of nanofluids decreased firstly with increasing shear rate (shear thinning behavior). Addition of nanoparticles into the base liquid enhanced the electrical conductivity up to 0.2 vol.% of Al2O3 nano-particles after which it decreased.