https://youtu.be/j-5Helm3KV4 #Subscribe#like#Share# Don’t forget to Like, Share & Subscribe to our Channel “KK-Chemistry (Karak-Chemistry) with Dr. Hussain Ullah” for more useful videos. #Fundamental of AnalyticalChemistry# # Units of Concentration #Normality#Number of equivalent# equivalent weight#Equiavelnt weight in acid base reactions# Concentration of Solution: It refers to the relative amount of solute (s) and solvent in a solution or Concentration means amount of solute dissolved in given amount of solution. In analytical Chemistry, the first step is the preparation of a solution of known concentration. The concentration of the solution is represented in different ways. 1. Normality (N) 2. Molarity (M) 3. Molality (M) 4. Parts per million (ppm) 5. Parts per billion (ppb) . 6 Parts per trillion (ppt) 7. Mole friction 8. Mass percent (%w/w) 9 Percent weight by volume (%w/v) 10Percent volume by volume (%v/v) 11. Percent volume by weight (%v/w) Skoog, D. A., West, P. M., Holler, F. J., Crouch, S. R., Fundamentals of AnalyticalChemistry, 9th ed., Brooks Cole Publishing Company, (2013). Christian, G. D., Analytical Chemistry. 6th ed., John-Wiley & Sons, New York, (2006). Harris, D. C., Quantitative Chemical Analysis, 8th ed., W. H. Freeman and Company, New York, USA, (2011). Bender, G.T. 1987. “Principles of Chemical Instrumentation” W.B. Saunders Co., London. Reilley, C. 1993. Laboratory Manual of Analytical Chemistry. Allyn& Bacon, London. Hargis, L.G. 1988. “Analytical Chemistry: Printice Hall Publishers, London. Egan's Fundamentals of Respiratory Care E-Book, Robert M. Kacmarek, James K. Stoller, Al Heuer. Egan's fundamentals of respiratory care,  James K. Stoller & Craig L. Scanlan & David C. Shelledy & Lucy Kester, 2003. ISC Chemistry Book 1 for Class XI (2021 Edition), R.D.MADAN. Basics for Chemistry, David A. Ucko. 11. Physical Chemistry For JEE (Main & Advanced) By Gurcharanam Academy Private Limited 12. Handbook of Chemistry Formulae for JEE & NEET By Career Point Kota By Career Point Kotat 13. Physical Chemistry for Engineering and Applied Sciences By Frank R. Foulkes 14. Super Course in Chemistry for the IIT-JEE: Physical Chemistry

1. 1
FUNDAMENTAL OF ANALYTICAL CHEMISTRY
Dr. Huusain Ullah
Ph.D (Chemistry)
Email: chem.hussain@gmail.com/chem_hussain@uo.edu.pk
Course Code: 2011

2. 2
In analytical Chemistry, the first step is the preparation of a solution of known
concentration. The concentration of the solution is represented in different ways.
Units of Concentration
1. Normality (N)
2. Molarity (M)
3. Molality (M)
4. Parts per million (ppm)
5. Parts per billion (ppb)
6. Parts per trillion (ppt)
7. Mole friction
8. Mass percent (%w/w)
9 Percent weight by volume (%w/v)
10Percent volume by volume (%v/v)
11. Percent volume by weight (%v/w)
Concentration of Solution: It refers to the relative amount of solute (s) and
solvent in a solution or Concentration means amount of solute dissolved in given
amount of solution.

3. 3
Normality is defined as the number of gram equivalents of solute present in one liter of
the solution. The solution of such a concentration is called a normal solution.
Normality or Normal Solution(N) :
Normality =
Liter of solution
Number of gram equivalent
A Normal solution is defined as a solution that contains one gram equivalent (one
equivalent) of the substance per liter of the solution. It is represented by N. 1N solution
of HCl contains 1.00 gm of H or 36,5 gm of HCl
Normality is similar to molarity except that equivalent are used instead of mole.
(1)
Normal Solution =
1L
36.5 g Hcl

4. 4
Number of gram equivalent:
The number of grams equivalent is equal to the weight of a substance in grams divided
by its equivalent weight
Number of gram equivalent =
Equivalent weight in grams of solute
Amount of the solute in grams or mass
The number of gram equivalent is just like (analogous) to the formula of moles i.e..,
no of moles = mass/molar mass (molecular weight).
Number of moles =
Molar mass or weight
Mass or weight in gram
(2)
By using equation (2) we can write equation (1) as eq (3) and (4)
Next slide, please

5. 5
Number of gram equivalent weight = 58.5 g
58.5 g NaCl
1
= 1 gEq
Number of gram equivalent weight =
58.5 g
29.5 g NaCl
1
= 0.5 gEq
Equivalent weight
Gram equivalent weight
To determine the number of gram equivalent weights in a substance, the gram weight
is divided by its calculated equivalent weight, as shown in the following examples:
Normality = Equivalent weight in grams of solute
Amount of the solute in grams
Liter of solution
Normality =
Equivalent weight × Volume of the solution in Liter
Amount of the solute in grams
(3)
(4)

6. 6
Normality =
Equivalent weight × Volume of the solution in Liter
Amount of the solute in grams
The above formula is based on the law of equivalent weights which states that the substances
react in the ratio of their equivalent weights/masses. i.e., the equivalent weight of NaOH is
40 gm and that of H2SO4 is 49 gm. Thus, 40 gm of NaOH will react with 49 gm of H2SO4 in
an acid-base reaction (eq 5 and 6). i.e, one equivalent of one substance (49 g of H2SO4 ) will
react with one equivalent (40 gm of NaOH)of another substance
Chemistry Book 1 for Class XI
(2021 Edition), R.D.Madan
This law of equivalent weight gives rise to another mathematical equation called the
dilution formula or normality formula.
N1V1 = N2V2
Dilution formula
Where N1, N2 are the normalities
of the solution, and V1 and V1
represent the volume of the two
solutions which react completely.
Equivalent of acid = Equivalent of base

7. 7
2NaOH
H2O
2Na + 2-OH
H2SO4
H2O
2H+ + SO4
2-
Equivalent weight =
40
1
= 40
Equivalent weight =
98
2
= 49
Number of replaceable entity
The equivalent weight in the normality formula can be written/ described as:
Reaction
Na2SO4 + 2H2O
Molar mass
Basicity or Number of replaceable entity (H+)
(5)
(6)
Equivalent weight =
Or gram equivalent weight Number of replaceable entity =X
Molar Mass in gram or gram molecular or
formula mass or atomic mass or ionic mass
Number of replaceable entity/ acidity of a base

8. 8
Equivalent weight or gram equivalent weight
The term equivalent is a combination of two words i.e., equi means same/equal/balance, and valent
or valency means charge/power. Collectively equivalent weight means the weight of substances
balanced by their charges. According to the law of equivalence, if two substances A and B are
involved in a reaction then the number of equivalence of A (H+ here) reacted = the number of
equivalence of B (-OH here) reacted. No excess reactants of A or B will remain.
NaOH
H2O
Na + -OH
HCl H+ + Cl-
the number of moles of H+ produced by HCl and the
number of moles of -OH produced by NaOH is called their
number of equivalent (or number of replaceable ions).
-OH and H+ have equal but opposite charges, combine
chemically and produce H2O
H2O
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In general, the equivalence of a substance is defined as the mass of the substance that reacts with or liberates
one mole of electrons.

9. 9
The equivalent weight of a substance/element is that weight of the element that will
combine with or replace directly or indirectly 1.0 gm (1 gm-atom) of H, 35.5 gm (1 gm-
atom) of Cl or 8.0 gm (1/2 gm-atom) of O.
2Mg + O2
2MgO
2 × 14 2 × 16
32 g
48 g
12 g 8 g
32 g of O2 = 48 g of Mg
8 g of O2 =
48 × 8
32
= 12g
Equivalent weight of Mg = 12 g
2 = 8 g
16 g
Gram Equivalent weight of O element =
Remember
Remember
Oxidation number
Mole or gm atomic wt
Gram Equivalent weight of an element =
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10. 10
Zn + H2SO4
68 .5 g 32.75 g
65.5
2
= 32.75g
Equivalent weight of Zn =
Similarly,
ZnSO4 + H2
Al + 3/2 Cl2
27 g 32.75 g
AlCl3
3/2 × 71 g
11.5 g of Cl = 27 g of Al
35.5 g Cl =
27 × 35.5
111.5
= 9.0 g of Al
Equivalent weight of Al 27
3
= 9.0 g of Al
= 1g
= 35.5g
Gram Equivalent weight of Cl element =
16 g
Gram Equivalent weight of H element = 1 = 1 g
1g
Gram Equivalent weight of H element =
Remember
= 1g
Gram Equivalent weight of H element = 1 = 35.5 g
35.5g
Gram Equivalent weight of Cl element =
Remember

11. 11
The replaceable entity (X) may be; the number of H+ ions in acids, -OH ions in base, the
number of electrons gained or lost by a species, number of cations in a species, etc.
depending upon the types of reaction/ titration in which it is involved. It is mostly used in
volumetric titrations or analysis.
Equivalent weight is a number when it is expressed in gram then it is called gram
equivalent weight (gEw) or gram equivalent (gEq). It is obtained by dividing the molar
or formula mass (weight) divided by the replaceable entity (X).
These reactions may be neutralization reaction/ titration, precipitation titration, or
complexometric titrations. Because the value of equivalent weight is different for different
types of reactions/titrations.
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By Career Point Kotat

12. 12
Equivalent weight =
Or gram equivalent weight Number of replaceable entity =X
Molar Mass in gram or gram molecular or formula mass or atomic mass
For acid X = number of H+ produced
For Base X = number of -OH produced
For redox species, X = the number of electrons gained or lost
For salt, X = Total +ive charge on cation or –ive charge on anion
It Will be discussed later
Number of replaceable entity =X
Valency of Na = 1
Equivalent weight =
Or gram equivalent weight 1
23 g Na
= 23 g
58.5 g NaCl = 58.5 g
=
1
Valency of NaCl =1 or one replaceable cation (Na+)
Total positive charge on cation (Na+)
Equivalent weight
Or gram equivalent weight
For the definition of equivalent weight, we must first know the behavior of a compound in a reaction.

13. 13
Equivalent Weight
1. Neutralization
Titration
2. Oxidation
Reduction Titration
3. Precipitation
Titration
4. Complexometric
Titration
Reminder:
For the equivalent weight, we must know the
nature of the reaction, otherwise, calculations of
this quantity will be impossible

14. 14
It is the weight of a substance that either contributes to or reacts with the 1gm formula
weight of hydrogen ion in that reaction. The milliequivalent weight is 1/1000 of the
equivalent weight. For an acid, base and its salt, the equivalent weight will be;
Equivalent weight in Neutralization Titration
Gram equivalent weight of an Acid
The gram equivalent weight of a mon, di, or polyacids is the weight of the acids in gram
that contains one mole of replaceable hydrogen. It can be calculated by diving its molar
mass in grams by the number of replaceable H+ ions in its formula.
1 mole of hydrogen (H) weighs 1 gram atom = atomic weight.
Reminder
Equivalent weight of Acid =
Basicity of Acid or number of replaceable entity=X
Molar Mass in gram or gram molecular or formula mass

15. 15
H2SO4
H2O
2H+ + SO4
2-
HCl
H2O
H+ + Cl- Equivalent weight =
36.5 g HCl
= 36g HCl per equivalent
i.e., 1 mole of HCl furnish 1 mole of H+ (1 equivalent)
The molar mass of HCl = equivalent weight of HCl
i.e., 1 mole of H2SO4 (98 g) = Produces 2 moles of H+ (one equivalent)
1/2 mole of H2SO4 (49 g) = Produces 1 mole of H+ (one equivalent)
So, One equivalent of an acid is the amount of that acid that can furnish 1 mole of H+ ions.
The equivalent weight of an acid is the mass in grams of 1 equivalent of that acid
×
1 mole HCl
1 mole HCl
1 equivalent
Equivalent weight =
98 g H2SO4
= 49g H2SO4 per equivalents
×
1 mole H2SO4
1 mole H2SO4
2 equivalents

16. 16
H3PO4
NaH2PO4 + H2O Equivalent weight =
98
1
Formula mass
= 98 g
NaOH
H3PO4
Na2HPO4 + 2H2O Equivalent weight =
98
2
= 49 g
2NaOH
H3PO4
Na3PO4 + 3H2O Equivalent weight =
98
3
= 32.66 g
3NaOH
Remember
The number of replaceable hydrogen atoms present in a molecule of an acid is
called the basicity of the acid.
Polyprotic acids like phosphoric acid (H3PO4), sulphuric acid, and carbonic acid
(H2CO3), the equivalent weight in such cases depends upon the reaction conditions.
While titrating H3PO4 against NaOH the H+ of H3PO4 reacts with the base (NaOH). And
hence, there are different equivalent weights are possible.

17. 17
H2SO4
H2O
NaHSO4 + H2O + CO2
+ Na2CO3 Equivalent weight =
98.0 g
1
= 98.0 g
H2SO4
H2O
Na2SO4 + H2O + CO2
+ Na2CO3 Equivalent weight =
98.0 g
2
= 49.0 g
It should be noted that the nature of the reaction in which H2SO4 takes part will
determine its exact gram equivalent weight (or mass). For example, in the reaction below
there are two different equivalent weights for H2SO4.
Another example is H2CO3 which has two replaceable H+ ions but under physiological conditions
only one H+ is replaceable. The gram equivalent weight of H2CO3 is the same as its gram formula
weight or 61 g.
H2CO3
H+ + HCO3
-
Equivalent weight = 61.0 g
1
= 32.0 g

18. 18
The equivalent weight of a base is its weight (grams) containing 1 mole of replaceable hydroxyl
(-OH) ions. Like acids, the gEq of a base is calculated by dividing gram molecular or formula
weight by the number of –OH groups in its formula.
Equivalent Weight of a Base:
Remember For ionic compounds, the word formula weight is used for its molar mass and
the molecular weight is used for covalent compounds
Equivalent weight of a bae =
Molar mass (weight) or Formula weight
Acidity of a base or number of replaceable –OH ion (X)
Equivalent weight of NaOH =
40 g NaOH
= 40g NaOH per equivalent
×
1 mole NaOH
1 mole NaOH
1 equivalent
Equivalent weight of Ca(OH)2 =
70.14 g Ca(OH)2
= 37.05g Ca(OH)2 per equivalent
×
1 mole Ca(OH)2
1 mole Ca(OH)2
2 equivalents

19. 19
The equivalent weight of a salt is that mass that contains 1 mole of replaceable cation or radical. Or
an equivalent mass of a salt is that mass of it which contains one gram equivalent of the metal or
radical or The equivalent weight of a salt is numerically equal to the molecular weight of the salt
divided by the total number of positive or negative charges.
Equivalent Weight of a Salt:
Remember For ionic compounds, the word formula weight is used for its molar mass and
the molecular weight is used for covalent compounds
Equivalent weight of a salt =
Molar mass (weight) or Formula weight
Total positive valency or negative
Equivalent weight of NaCl =
1
= 58.5 g
58.5
Equivalent weight of CaCO3 =
2
= 50.0 g
100

20. 20
Calculate the number of grams equivalent in 40 gm of NaOH. The molar mass of NaOH is 40 g.
Example:
Solution:
AS we know that
Number of gram equivalent =
Equivalent weight in grams of solute
Amount of the solute in grams or mass
But
Equivalent weight of a bae =
Molar mass (weight) or Formula weight
Acidity of a base or number of replaceable –OH ion (X)
Equivalent weight of a bae =
1
40 gm
= 40 gm
Number of gram equivalent =
40 gm
40 gm = 1 gEq

21. 21
Assignment-1
Determine the equivalent weights of the following acids, bases, and salts.
Acids: HNO3, C2H5COOH
Bases: Mg(OH)2, LiOH
Salts: KCl , Na2CO3, Fe2SO4.7H2O
How can you prepare a 0.1 N solution of NaOH in a 100 mL aqueous solution?
Assignment-2
Comment Please
What mass of magnesium hydroxide is needed to prepare 1.50 L of a 0.1 N solution?

22. 22
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