Conductometric Titration

What is Conductometric Titration, and how does it work?

Conductometric titration is a quantitative laboratory method for determining the concentration of a particular analyte in a mixture. Conductometric titration continuously adds a reactant to a reaction mixture and documents the resulting change in the reaction mixture's electrolytic conductivity. The conductivity of an electrolytic solution is set on by the number of free ions in the solution. The charge assigned to each of these ions.
An abrupt change in conductivity after the continual addition of the titrant indicates that the stoichiometric point has been achieved in this titration method. In the conductometric titration procedure, the change in the hydroxyl and hydrogen ions concentration is connected to an increase or reduction in electrolytic conductivity.
Conductometric titration using a standard solution of a base can be used to assess an acid's strength. Conductometric titration is particularly useful for titrating homogeneous suspensions or colored solutions, which cannot be done with conventional chemical indicators.

Principle

The conductometric titration technique works on the following principle: one ion is replaced with another during the titration process, and the difference in the ionic conductivities of these ions directly affects the overall electrolytic conductivity of the solution.
The ionic conductance values of cations and anions differ. Finally, the conductivity of an electrolytic solution is affected by the presence of a chemical reaction.

Theory

The principle behind this sort of titration is that conductivity measurement can determine the endpoint of the titration process. For example, in a neutralization reaction between an acid and a base, adding the base lowers the solution's conductivity at first. This is because the cationic component of the base would replace the H+ ions.
The concentration of ionic entities will increase after the equivalence point is achieved. As a result, the solution's conductance increases. When the conductance values are represented visually, two straight lines with opposite slopes will result. The equivalence point is where these two lines intersect.

Process

The general procedure for conductometric titration of an acid with a base is as follows:

• Dilute 10 mL of acid with roughly 100 mL of purified water.
• The base must now be poured into a burette, and the starting volume must be recorded.
• A conductivity cell must be put into the diluted acid solution so that both electrodes are fully immersed at this stage.
• To obtain an initial reading, the conductivity cell can now be connected to a digital conductometer.
• The base should be added dropwise into the acid solution. The amount of base added and the change in conductance must be recorded.
• The solution's conductance has increased dramatically, indicating that the endpoint has been reached. After the titration's endpoint, however, a few more readings are required.
• The observed values must now be graphically plotted. The point of intersection between the two lines can be used to determine the equivalence point.

The acid's strength may be determined using the formula
S2 = (V1S1)/10,
where,
S2 = acid's strength
V1 = volume of base added
S1 = strength of the base
Thus, the acid (V2) has a volume of 10 ml in this case.

Conductometric Titration's Benefits and Drawbacks

The conductometric titration procedure has several advantages, which are stated below.

• This method is particularly effective for titrations of dilute solutions and weak acids.
• Compared to a few other titration methods, the endpoint of this approach is exceedingly sharp and exact.
• This titration method is used for colorful or turbid liquids where the endpoint of the titration using standard indications is challenging to see with the naked eye.
• Acid-base titrations, redox titrations, precipitation titrations, and complicated titrations all use conductometric titration

The following are the two significant drawbacks of this method of titration:

• UOnly a few particular redox titrations can be performed using this method. In addition, because of the large concentration of hydronium ions in the solution, the conductivity of the solution is obscured.
• When the electrolyte concentrations are high, the accuracy of conductometric titration is low, making the titration procedure undesirable.