Conductometric titration is a type of titration in which the electrolytic conductivity of a mixture of samples is continuously determined with the addition of a reagent. The equivalence point is the situation where the conductivity of the reaction mixture undergoes a sudden change. The electrical conductivity of the sample solution depends on the number of free ions in the sample and the charge parallel to each of them. Conductometry has an important application in analytical chemistry, where a standard technique is conductometric titration.
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Principle of conductometry:
To determine the ability of a substance to carry electric current, conductivity is used. Siemens conductance g is the basic unit and is the reciprocal of resistance and is determined in ohms. The electrical conductivity of the sample is proportional to the number of ions it contains and therefore calculating the conductivity of the solution will provide a reading.
Principle of operation by which conductivity is calculated in the simple system. Two conductivity plates are placed in the solution and optionally applied, then the current (usually an alternating voltage) is calculated. From the current and voltage values, the conductivity can be found. Accurate and consistent conductivity can be measured by multiplying the conductivity by the electrode cell.
This constant conductivity is determined by the formula below,
Gt = Gt is needed { 1 + a (t - t is needed) }
Where Gt is the conductivity at any temperature in °C
G tcal is the conductivity at a calibration temperature in °C
a is the temperature coefficient of the solution
t the calibration temperature is required.
This adjustment can be done manually or automatically by calculating the temperature coefficient of the solution with advanced conductivity meters. Automatic temperature compensation with dedicated temperature sensors is required for reliable conductance measurement, and the sample and standard solution must be calibrated at the same temperature.
Type of conductometric titration:
There are generally five types of conductometric evaluation, listed below.
1. Acid-base titration: It is a quantitative analysis process to determine the concentration of acid or base, neutralizing it precisely by means of a standard solution with a recognized concentration.
2. Precipitation assessment: Precipitation titration is a titrimetric method that involves the formation of precipitates throughout the titration process.
3. Substitute Valuation: The metal can be determined by this method when direct or subsequent titration does not provide an accurate endpoint or when suitable indicators are not available for the molecules.
4. Redox titration (redox): It is a type of conductometric titration, redox titration is a reduction by an oxidizing agent. Typically, this titration involves a redox potentiometer or indicator.
5. Complexometric titration: In this titration, the color complex is used to determine the endpoint, it is a type of titrimetric analysis.
Conductometric titration procedure:
- Take 30 mL of 0.001 M HCL in a beaker (100 mL).
- Fill the burette with NaOH solution.
- Switch on the conductivity meter.
- Clean the conductivity cell and temperature probe with distilled water and wipe gently with tissue paper.
- Immerse the conductivity cell in the HCL solution.
- Press the conductivity key.
- The device will display the behavior.
- While continuing to mix, add NaOH in HCl.
- Write down the readings.
- Plot the graph of conductance versus volume of NaOH.
- Turn off the instrument and clean the conductivity cell and temperature probe.
Conductometric titration applications:
- Conductometry is also used to find salinity concentration and total dissolved solids (TDS).
- The purity of water can be determined by conductimetry.
- The solubility of sparingly soluble salts such as lead sulphate, sulphate and barium is determined by conductivity.
- The alkalinity of fresh water can be determined by this method.
- Conductometric titration has various applications in precipitation titration, redox titrations, acid-base titration and complex titrations.
- It can be used to track microorganisms.
- Conductometry is used to follow the progress of a chemical reaction.
- The chemical equilibrium in ionic reactions can be determined by it.
The advantages of conductometric titration are as follows.
- Conductometric titration is simple and has high selectivity.
- It is also suitable for complex samples, such as turbid suspensions, low concentrations and colored solutions, etc.
- Provides accurate results with minimal errors.
- Conductometric titration is also suitable for weak acids and more dilute solutions.
- The endpoint of some samples (colored or turbid) is not visible to the naked eye. In this case, conductometric titration is used.
- The temperature remains constant throughout the process.
The disadvantages of conductometric titration are as follows.
- It is not possible to measure samples with high concentrations by this method.
- It is less accurate than the other methods.
- Changes in salt levels can increase the conductivity of the solution.
- Only a limited number of redox titrations can be performed.
The most frequently asked questions about conductometric evaluation are as follows.
What is conductometry?
Conductometry is the determination of electrolytic conductivity to observe the progress of a chemical reaction. It is generally used to measure the total conduction of a solution.
What is the basic principle of conductometric evaluation?
The main principle involved in conductometric titration is that the movement of ions produces electrical conductivity. The movement of ions mainly depends on the concentration of ions
What are the types of conductometric titration?
Acid-base titration, redox (redox) titration, complexometric precipitation titration and substitution titration are the types of conductometric titration.
What is the main advantage of conductometric titration?
The main advantage of conductometric titration is that it can determine colored or turbid solutions and can work with many dilute solutions and weak acids.
What is the main difference between conductometric titration and potentiometric titration?
The main difference between conductometric and potentiometric titration is that conductometric titration determines the electrolytic conductivity of the sample solution whereas potentiometric titrations determine the potential of the sample solution.
