This document discusses conductometry, which is the measurement of a solution's ability to conduct electricity. Conductance depends on temperature, ion nature, concentration, and electrode size. Equivalent conductance is defined as conductance between 1 cm electrodes of 1 gram equivalent of solute per liter. At infinite dilution, equivalent ionic conductance is the sum of individual ion conductances. Conductivity is measured using a conductivity bridge and conductance cell. Conductometric titrations can be used to determine purity, physical constants, incomplete reactions, and mixtures. Curves of conductivity versus titrant volume are shown for strong acid-strong base and weak acid-strong base titrations.

1. Conductometry

2. Introduction
• Conductance: is the ability of the medium to
carry the electric current.
• migration of positively charged species
towards the cathode and negatively charged
ones through the anode
R
1
G 
i
E
R 
From Ohm low
ohm-1(seimen)
E is the potential difference,
i is the current intensity.

3. The conductance of the solution depends on:
1. Temperature:
It is increased by increase of temperature.
2. Nature of ions
size, molecular weight, number of charges the ion carries and other factors
3. The concentration of ions:
As the number of ions increases the conductance of the solution increases.
4. The size of the electrodes
L
A
K
G 
A
L
G
K 
L/A is cell constant
K is the specific conductance or conductivity
ohm-1cm-1 or seimen/cm.

4. • Equivalent conductance 
It is defined as the conductance of one gram equivalent of solute
contained between electrodes spaced one centimeter apart.
Where C is the concentration in gram equivalent per liter.
• Equivalent ionic conductance:
• At infinite dilution, interactions become nil;
the overall conductance of the solution consists
of the sum of the individual equivalent ionic
conductance
• o = +
o + -
o

6. Instrumentments
• Two parts:
1. conductivity bridgee.
BC
AC
R
R
R
R
R
R
R
R
R
R
s
x
CB
AC
s
X
AC
x
CB
s



x
-
100
x
.
R
1
G
X
BC
100
AB
AC
BC
.
R
1
G
1












7. 1. Conductance cell

12. Application of conductivity
1. Direct or absolute measurments
1. checking purity of distilled water or other chemicals.
2. determination of physical constants such as
ionization constant.
2. Conductometric titrations
1. Very dilute solutions.
2. Turbid and highly coloured solutions.
3. Reaction which is not complete and where there is no suitable
indicator,
e.g. reaction between weak acid and weak base.

13. 1. Titration of strong acid with strong base:
The reaction is represented by the following equations
e.g. H+ + Cl- + Na+ + OH-  H2O + Na+ + Cl-

14. 2. Very weak acid with strong base or a very
weak base with stronger acids

15. • Determination of mixture of hydrochloric acid
(strong acid) and acetic acid (weak acid) with
sodium hydroxide (strong base)

16. 3. Precipitation and complex formation reaction
Na+ + Cl- + Ag+ + NO3
-  AgCl + Na+ + NO3
-

17. Conductivity as a function of the volume of added standard
solution in the titration of an approximately 0.1 molar acetic
acid solution (V = 5 ml) with a sodium hydroxide solution (c =
0.1 mol · l-1)