Conductance of electrolytic solution

Difference between electronic &
electrolytic conductors
e
(3) Conduction decreases with
increase in temperature
(2) Flow of electricity is due to the
movement of ions
(2) Conduction is due to the flow of
electron
(1)Flow of electricity takes place by the
decomposition of the substance.
(1) Flow of electricity take place
without the decomposition of
substance.
EResistance refers to the opposition
to the flow of current.
For a conductor of uniform cross section(a)
and length(l); Resistance R,
a
lThe reciprocal of the resistance isSpecific conductance ! = 1
"
Specific Conductivity
! = !
a
"
#
$ %
&
x Conductance
Unit of specific conductance is ohm–1cm–1
SI Unit of specific conductance is Sm–1 where S is Siemen
a But ? = R
l
K
a.R
? = l
l/a is known as cell constant
Conductance of unit volume of
cell is specific conductance.
Equivalent Conductance
Where, ? = Specific conductivity
V = Volume of solution in cc. containing one gram equivalent of
the electrolyte.
It is the conductance of one gram equivalent of the electrolyte
dissolved in V cc of the solution.
Equivalent conductance is represented by
?
Mathematically, ! =k " V
! = k "
1000
Normality
Effect of Dilution on Conductivity
Specific conductivity decreases on dilution.
Equivalent and molar conductance both increase with dilution and
reaches a maximum value.
The conductance of all electrolytes increases with temperature.
concentration, (mole L ) –1 1/2
CH COOH (weak electrolyte) 3
KCl
called conductance. It is denoted by C.
C=1/R
Conductors allows electric current to pass through them.
Examples are metals, aqueous solution of
acids, bases and salts etc.
Insulators do not allow the electric current to pass
through them.
Examples are pure water, urea, sugar etc.
R !l and R !
l
a
"R = #
l
a
Where is called resistivity or
specific resistance.