Page 53 - Pharmaceutical_Analytical_Chemistry_1_Theoretical_Notes_Level_1

Mansoura National University
Pharm D-Clinical Pharmacy Program Level 1 Pharm. Anal. Chem. 1 (PC 101)

What is the normality of 3 M What is the molarity of 6 N
H2SO4? H3PO4 ?
Solution: Solution:

• 1 M H 2SO 4 = 2 N H 2SO 4 • 1 M H 3PO 4 = 3 N H 3PO 4

3 M H 2SO 4 = X N H 2SO 4 x = 6 N H 3PO 4

• X = 3×2 = 6 N • x = 6×1 = 2 M
1 3

Relation between concentrations of two reacting solutions

OR
How we calculate the concentration of the sample from the

concentration of the standard?

1) First Method (the method used in pharm. quality control)

1- Calculation of Equivalence Factor (F) {1 ml of standard 
? g of sample}

2- Calculation of Concentration in w/v {g/L, mg/L, g%, mg%}

{for more details refer to the practical course}

2) Second Method
If we use normal concentrations: e.g.

N1 V1 = N2 V2 H2SO4 + 2 NaOH → Na2SO4 + 2 H2O

If we use molar concentrations:
N1 V1 = N2 V2
M1 V1 M2 V2
=

H2SO4 NaOH
n1 and n2 are the number of moles
in a balanced chemical equations. M1 V1 = M2 V2

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