Page 83 - Pharmaceutical Analytical Chemistry III

❑DETERMINATION :

 "Nessler's reagent method“

Nessler’s reagent = K2HgI4 / KOH

(dipotassium tetraiodo- mercurate in alkaline solution)

NH4+ + OH- ⎯→ NH3 + H2O

Saline Free

NH3 + 2 K2HgI4 + KOH ⎯→ NH2Hg2I3 + 5 KI + H2O
Free Nessler’s reagent yellowish

brown color