This document is a chemistry project report submitted by Ayushi Gupta of Class XII. The project discusses the conductance of electrolytic solutions. It defines electrolytes and explains that they conduct electricity in solution due to the ions formed. It then discusses various topics related to conductivity of electrolytes like specific conductivity, equivalent conductivity, molar conductivity, and their relationships. It also describes how conductivity of electrolytic solutions is measured using a conductivity cell and Wheatstone bridge. Kohlrausch law relating limiting molar conductivity of electrolytes to their constituent ions is also explained.

1. CHEMISTRY PROJECT ON
“CONDUCTANCE OF ELECTROLYTIC
SOLUTION”
NAME - AYUSHI GUPTA
CLASS – XII ROSE
ROLL NO. –
SUBJECT – CHEMISTRY
SCHOOL – CHRIST JYOTI SENIOR SECONDARY
SCHOOL, SATNA (M.P.)
SUBMITTED TO – SUJA MAM

2. ACKNOWLEDGEMENT
I under took this project work as part of our XII, I had tried to apply
my best of knowledge and experience gain during the study in class
work experience.
I would like to extent my sincere thanks and gratitude to our
MADAM MRS. SUJA ABRAHAM.
She helped to understand and remember important details of my
project. It has been successful only because of her guidance.
AYUSHI GUPTA
CLASS – XII (SCIENCE)

3. CERTIFICATE
This is to certify that AYUSHI GUPTA student of class - XII ROSE of
CHRIST JYOTI SENIOR SECONDARY SCHOOL has successfully
completed her project Work entitled “CONDUCTANCE OF
ELECTROLYTIC SOLUTION” under my guidance. She has taken proper
care and shown sincerity in completing the project.
I certified that project is up to my expectation and as
per the Guidance of CBSE.
MRS. SUJA ABRAHAM
Examiner:-
Name: _______________
Signature:

4. PERMISSION LETTER
To
Mrs. Suja
Christ Jyoti Higher Secondary School
Satna (M.P.)
Subject – To grant permission for preparing chemistry project
Respected Madam,
This letter is to get the permission from you
for completing my project on CONDUCTANCE OF ELECTROLYTIC
SOLUTION for annual examination of informatics practices under
your guidance.
Thanking You
Project Leader Project Mentor
Name – Ayushi Gupta Mrs. Suja Abraham
Roll No. -

5. TABLE OF CONTENT
S. No. Topic Page No.
1 Conductance of electrolytic solution 1
2 Conductance of electrolyte 2
3 Specific conductivity 4
4 Equivalent conductivity 6
5 Molar conductivity 7
6 Relation between equivalent conductivity and
molar conductivity
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7 Conductivity cell 9
8 Wheatstone bridge 10
9 Koulraush law 12
10 Bibliography 15

6. Conductance in Electrolytic Solutions
Electrolytes and nonelectrolytes are two types of water-soluble
compounds. Electrolytes are electrovalent compounds that create
ions in solution. Due to this, electrolytes conduct an electric current
in the solution. Electrolytes include sodium chloride, copper (II)
sulphate, and potassium nitrate. Nonelectrolytes, on the other hand,
are covalent compounds that provide neutral molecules in solution.
Nonelectrolytes do not conduct electricity. Nonelectrolytes include
sugar, alcohol, and glycerol. As a result of the passage of electric
current through its solution, an electrolyte invariably experiences
chemical decomposition. The conductance of electricity by ions
present in solutions is called electrolytic conductance or ionic
conductance. Conductivity of electrolytic solution depends on
following factors:
•Nature of electrolyte
•Size of ions produced and their solution
•Concentration of electrolyte
•Temperature (conductance increases with increase in temperature)
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7. Conductance of Electrolytes
Electrolyte solutions conduct electric currents by allowing ions to
flow between electrodes. Conductivity, or conductance, is the ability
of electrolytes to conduct electric currents. Electrolytes, like metallic
conductors, follow Ohm’s law. The following relation provides the
current I passing through a metallic conductor according to this law.
I=E/R
Where, E is the potential difference between two points (in volts),
and R denotes the resistance in ohms (or Ω). A conductor’s
resistance R is proportional to its length, l, and inversely
proportional to its cross-sectional area, A. That is,
R ∝ l/A
Or
R = ρ × l/A……(1)
2

8. ρ “rho” is a proportionality constant known as resistivity or specific
resistance. Its value is determined by the conductor’s material. We
can write from (1):
ρ = R×A/l
If l=1 cm A=1 sq.cm, then:
ρ = R
As a result, a conductor’s specific resistance is defined as the
resistance in ohms that one-centimeter cube of it provides to the
passage of electricity.
3

9. Specific Conductivity
It is self-evident that a substance with a low resistance to current
flow allows more current to travel through it. Thus, conductance,
or the ability of a substance to conduct electricity, is the inverse of
resistance. The reciprocal of specific resistance is known as Specific
conductivity or conductivity.
It is defined as the conductance of a solution of an electrolyte in a
centimetre cube (cc). The specific conductivity is denoted by the
symbol k (kappa). Thus,
k = 1/ρ = 1/R × 1/k
l/A known as cell constant.
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10. Units of Specific Conductivity
In general, conductance is measured in
reciprocal ohms (r.o), mhos, or Ohm-1. The
following formula can be used to calculate
its unit:
k=1/A × 1/R × l/ohm × cm/cm2
ohm–1cm–1
Variation of Specific Conductivity with Concentration
Specific conductivity is the conductivity due to the ions present
in 1cc of the solution. Therefore, as the concentration increases,
specific conductivity increases.
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11. Equivalent Conductivity
It is the conducting power of all the ions furnished by one gm
equivalent of an electrolyte present in a definite volume of
solution.
It is represented by Λeq. When concentration is changed, the
number of ions present in 1 cc of the solution also changes, and
consequently conductivity of the solution changes.
Λeq = K/Ceq
k = Specific conductivity, Ceq = Concentration of the solution in gm
eq/unit volume
Λeq = k .Veq (Vm = Volume in cc of the solution containing one gm
equivalent of electrolyte.)
Veq = 1000/N [N=Normality]
Λeq = K . 1000/N
Unit = ohm–1cm2eq–1 or Scm2eq–1
6

12. Molar Conductivity
It is the conducting power of all the ions furnished by one mole of
an electrolyte present in a definite volume of the solution.
It is represented by Λm.
Λm = k/Cm
Cm = The molar concentration of the solution
Λm = k.Vm (Vm = Volume in cc of the solution containing 1mol of
electrolyte.)
Λm = k.1000/M (M= Molar concentration)
Unit : Ω-1cm2mol–1 Or S cm2mol-1.
7

13. Relationship Between Molar Conductivity and Equivalent
Conductivity
Λm/Λeq = k/k × 1000/M × N/1000 = N/M
Λm/Λeq = Molar mass / Equivalent mass
Measurement of Electrolytic Conductivity
The conductance of a solution is the reciprocal of its resistance.
Therefore electrolytic conductivity of a solution can be measured by
measuring the resistance of the solution. The resistance of an
electrolytic solution is measured by using a special type of cell known
as Conductivity Cell and a Wheatstone Bridge.
8

14. Conductivity Cell
The glass apparatus used for measuring the resistance of a
definite volume of a solution is called a conductivity cell.
It is made of Pyrex glass and is fitted with two platinum
electrodes fixed at a certain distance from each other.
Conductivity cells are of different types. Some commonly used
conductivity cells are shown in Figure.
9

15. In a conductivity cell, the distance l between the two electrodes
and the area A of the electrodes are fixed. Therefore, the
quantity l/A is a constant for a particular conductivity cell. This
quantity is termed cell constant. Thus,
Cell Constant = l/A
The unit of Cell Constant is cm-1.
Wheatstone Bridge
Wheatstone Bridge is an important device
used for the measurement of the resistance
of a wire or of an electrolytic solution. It
consists of four arms having resistances R1,
R2, R3 and Rx connected together through a
galvanometer Vo, a battery VEX as shown in
Figure. Resistance R2 is variable, while resistance Rx is an unknown,
i.e., whose value is to be measured.
10

16. Resistances R1 and R3 are known. After completing the circuit with
the help of key K, the variable resistance R2 is adjusted in such a
way that a null point is obtained i.e., there is no deflection in the
galvanometer. At this stage, according to the Wheatstone Bridge
Principle
R1/Rx = R2/R3 Or Rx R1R3 / R2
Knowing the values R1,R2 and R3, the value of unknown
resistance Rx can be determined.
Limiting Molar Conductivity
The molar conductivity of a solution at infinite dilution is known as
limiting molar conductivity.
11

17. Kohlrausch Law
Kohlrausch Law relates to the limiting molar conductivity of an
electrolyte to its constituent ions.
It basically states that the limiting molar conductivity of an
electrolyte is equal to the sum of individual limiting molar
conductivities of the cations and anions which make up the
electrolyte.
This law is also popularly known as the Kohlrausch Law of
Independent Migration.
Kohlrausch law and its applications are very important in the study
of dilute solutions and also in the study of electrochemical cells.
This law is mainly used to find the limiting conductivity of a weak
electrolyte, among other important applications.
12

18. An example of this law is the limiting conductivity of sulphuric
acid(H2SO4). The limiting molar conductivity of sulphuric acid is
equal to the sum of the limiting conductivities of hydrogen cation
and sulphate anion.
The mathematical representation of the above statement is,
λ∞
H2SO4 = 2 λ∞
H+ + λ∞
SO2−4
Here, λ∞ is the limiting molar conductivity.
Applications of Kohlrausch Law
- It is used to calculate the dissociation constant of an electrolyte.
- It is used to calculate the limiting molar conductivity of a weak
Velectrolyte.
- The degrees of dissociation of weak electrolytes are also found
Vusing this law.
13

19. - Solubility constants of various salts are also calculated using this
Vlaw.
- It is also used in the calculation of the cell potential in various
Velectrochemical cells
14

20. BIBLIOGRAPHY
I Ayushi Gupta of class XII Rose, have completed this project
file with the help of my subject teacher.
I used the following links and books to finalise my file:-
• http://www.byjus.com/
• http://www.toppers.com/
• NCERT TEXTBOOK
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