Its is very helpfull for students of graduation . it contains basics of conductometry.

1. Prepared By
Asmita S. Satao
M.Sc. Sem- 2 (Analytical Chemistry)
Fergusson College, Pune (MH)
CONDUCTOMETRY

2. Synopsis
• Introduction to Conductance
• Introduction to Conductometry
• Historical Background
• Principle of Conductomerty
• Instrumentation
• Instrumentation: Current Source
• Instrumentation: Conductivity Meter
• Instrumentation: Conductivity Cell
• Instrumentation: Electrode
• Working of Conductometric Device
• Application of Conductometry
• Advantages of Condtuctometry
• Disadvantages of Conductometry

3. Introduction to Conductance
• The conductance is the flow of electricity through
electrolytic solution due to migration of ions by applying
potential difference between two electrode.
• Cathode (-ve charged) will attracts cations (+ve) .
• Anode (+ve charged ) will attracts anions (-ve ).
• Conductance (G) is inversely proportional to the resistance
(R).
G=1/R
• Unit of conductance is siemens/meter (S/m).

4. Introduction to Conductometry
• The measurement of electrical conductivity of solution
during chemical reaction is called as conductometry.
• It is determination of quality material present in mixture
by measurement of its effect on electrical conductivity of
mixture.
• Conductometry is often applied to determine the total
conductance of solution or to analyze the end point of
titration that include ions .

5. Historical Background
• Measurement of conductance began as early as the 18th
century , when Andreas Baumgartner noticed that salts
and mineral waters from the town Bad Gastein in Austria
conducted electricity.
• First time conductometry is used in the year of 1776 for
the determination of purity of water.
• Friedrich Kohlraush further developed conductometry in
1860.
• Conductometry was first improve with the development
of the glass electrode in 1909.

6. Principle of Conductomerty
• Conductometry is based on the principle of
determination of change in conductivity .
• Change in conductance is due to replacement of ions
with each other.
• Ionic conductivity is different for different ions.
• For example, If we carry out reaction in between HCL
and NaOH then in this reaction H+
ions replaced by Na+
ions then conductivity decrease because conductivity of
H+
is higher than Na+
.
• Movement of ions is mainly depend upon the
concentration of ions .

7. Instrumentation
1) Digital Display
2) Calibrator.
3) Power switch.
4) Burette.
5) Titrant.
6) Anode.
7) Cathode.
8) Magnetic Stirrer.

8. Instrumentation: Current Source
• Alternative current (AC) is used as source .
• High frequency AC generator is employed .
• Electrical potential is applied, ions will be transferred and
intimately conductance takes place.
• DC current is not used because electrode become
polarized leading to high cell resistance.

9. Instrumentation: Conductivity Meter
• Conductivity meter mainly consist of three components.
1). Digital display. :-
1. It display the conductance .
2. Conductance can be measured in micro Siemens and mili Siemens
depending upon the conductivity of ions.
2). Calibrator. :-
1 . Before we measure the conductance we have to Calibrate the
instrument.
2 . Calibration method is given on instrument.
3). Power switch. :- To turn on/off the instrument Power switch is used.

10. Instrumentation: Conductivity Cell
• It is made up of Quartz or Pyrex.
• In conductivity cell there are three types of cells.
1) Low concentration measurement.
1.It contains a jar in which two electrodes are dipped in solution .
2. Electrode made up of platinum.
2) For precipitate type of reaction.
1. Precipitate type of conductometric titration can be carried out
satisfactorily if the ensuring reaction product is sparingly soluble
or having stable complex.
2. It contains magnetic stirrer. Due to magnetic stirrer precipitate
does not stick on surface of electrode and you get proper reading.

11. Instrumentation: Conductivity Cell
3) Dipped type
As it is convenient to dipped in solution due to its
compressed sized.
(A) (B) (C)

12. Instrumentation: Electrode
• Made up of Platinum (Pt).
• Surface area of electrode is 1 cm2
.
• Distance between two electrode is 1 cm.
• Electrode are coated with platinum black to avoid
polarization and to increase surface area.

13. Working
• Firstly Calibrate the instrument.
• A burette must be filled with the base and the initial volume
must be noted.
• A conductivity cell must be inserted into the diluted acid
solution in such a way that both the electrodes are completely
immersed.
• The conductivity cell can be connected to a digital
conductometer in order to obtain initial reading
• Then the base added drop wise into the acid solution. The
volume of base added must be noted along with the
corresponding change in the conductance.

14. Continue. . .
• A sharp increase in conductance of the solution implies
that end point has been reached.
• The observed value must be now plotted graphically.
• The equivalence point can be obtained from the point
of insertion between the two lines.

15. Applications
• To check water pollution in lake, rivers and other water
reservoir.
• It is also used to check alkalinity of fresh water.
• Salinity of sea water can be checked by this method.
• It is also used to trace antibiotics.
• Used for tracing microorganisms in food microbiology.
• Purity of distilled water can be determined.
• To check solubility of sparingly soluble salts.

16. Advantages
• The measurement process of conductivity is quite
simple.
• Provide accurate results with minimum errors.
• By graph endpoint can be determined.
• Suitable for the analysis if weak bases , weak acids ,
combination of strong and weak acids.
• This method is also suitable for turbid solution.

17. Disadvantages
• Only few specific redox titration can be done with the
help of this process. This is because of conductivity of
the solution is masked by relatively high hydronium ion
concentration.
• The accuracy of comductometric titration is low when
conversion of the electrolytes are high , making the
titration process unsatisfactory.

18. Thank You !!!