Page 30 - Feed Lab

Reagents and Chemicals Suguna Management System Ver 1.0 / SOP / FQL / P1 - 04 Page 2 of 6

Molarity, Molality, percentage, ppm, ppb etc. The equivalent weight of sulphuric acid

FNormality: It is defined as the number of gram = (1.008 x 2 +32 x 1 + 16 x 4 )
equivalents of a substance in one litre of a solution 2
(for eg., the equivalent weight of a NaOH is 40. So
98.016
40gm in 1 litre of solution is 1N NaOH solution. = = 49.08
2
FMolarity: It is defined as number of moles of the
substance in one litre of the solution. (1 mole
means one-gram molecular weight in the case of a 2. Base
molecule, one-gram atomic weight in the case of The equivalent weight of base = Molecular weight
an atom, one-gram ionic weight in the case of an Acidity
ion) Acidity is the number of replaceable hydroxyl ions in
one molecule of the base.
FMolality: It is defined as the number of moles of the
substance in 1000g of the solvent. For eg.,
For NaOH it is 1
FPercentage: W / V %, V / V % is in use.
For CaOH, is is 2
W / V is the number of grams of the substance in For Al (OH) , it is 3
3
100 ml of the solution.
For eg,
V / V is the number of ml of the substance in 100 ml
of the solution. The equivalent weight of NaOH

FPpm: Parts per Million (or) mg/Kg (22.99 x 1 + 16 x 1 + 1.008 x 1)
= = 40
FPpb: Parts per Billion (or) µg / kg 1

3. Salt
EQUIVALENT WEIGHT
Normality of the equivalent weight is defined as that The Equivalent weight of a salt is that which combines
weight of it which combines with or displaces 1.008 with one equivalent of an acid or a base.
parts by weight of hydrogen or 8 parts by weight of For eg.,Na CO combines with 2 moles of HCl as
oxygen or 35.5 parts by weight or 35.5 parts by weight 2 3
follows.
of chlorine or one-gram equivalent weight of any other
element. Na CO + 2HCl ------ 2NaCl + H O + CO 2
2
3
2
106 73
EQUIVALENT WEIGHT OF COMPOUND
Here 73 parts by weight of the acid combines with 106
parts by weight of the salt. Hence 36.5 parts by weight
1.Acid
Molecular weight
Equivalent weight of an acid = of acid will combines with 106 x 36.5 /73 = 53.
Basicity Equivalent weight of Na CO = 53
2
3
Basicity is the number of replaceable hydrogen in one
molecule of the acid. Preparation of Std. 0.1N solution
Equivalent Weight
For HCl, the basicity is 1.
Std 0.1N solution = ------------------------------- X 100
For H SO , the basicity is 2 Minimum Assay
2
4

For H PO , the basicity is 3 = X gm / Lit
4
3
For eg,

Prepared by : Approved by :
20 Director - Technical