Page 95 - Pharmaceutical_Analytical_Chemistry_1_Theoretical_Notes_Level_1
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Mansoura National University
Pharm D-Clinical Pharmacy Program Level 1 Pharm. Anal. Chem. 1 (PC 101)
➢ Boiling is necessary for the reaction between NH Cl and NaOH to remove the
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produced ammonia.
➢ This method requires Blank Determination, which is a separate determination in
which we repeat the same steps of the experiment but without the sample and the end
point in this case is called (Blank Reading).
❖ Why blank determination is required in this experiment?
Because when NaOH is heated and then cooled, its strength is decreased due to:
1- Interaction of NaOH with the glass of the flask.
2- Absorption of atm. CO .
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