Page 92 - Pharmaceutical_Analytical_Chemistry_1_Theoretical_Notes_Level_1

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

Determination of HCl & CH COOH mixture
3
The principle depends on double-indicators (two-indicators) method.

st
1 Flask: (E.P for HCl only)
M.O.
Direct titration of the mixture ≠ stand. NaOH using M.O. ind.

E.P ≡ HCl only
M.O.
nd
Principle 2 Flask: (E.P for total HCl & CH COOH)
ph.ph. 3
Direct titration of the mixture ≠ stand. NaOH using ph.ph. ind.
E.P ≡ HCl + CH COOH
ph.ph. 3

(E.P - E.P ) ≡ CH COOH
ph.ph. M.O. 3
For HCl:
HCl + NaOH → NaCl + H O
Equations 2
For CH COOH:
3
CH COOH + NaOH → CH COONa + H O
3 3 2

Titration

Curves

87