Iodine azide reaction
The iodine-azide reaction is used to detect sulfide by reacting with iodine / azide in qualitative inorganic analysis. Pure solutions of sodium azide (NaN 3 ) and iodine (I 2 ) are stable together for a long time. However, they are catalytically decomposed by the action of S 2− (also sparingly soluble heavy metal sulfides). Thiocyanates (SCN - ) react analogously.
- Sulphide anions and iodine react to form sulfur and iodide. (Discoloration)
- Sulfur and azide ions react to form sulfide and molecular nitrogen. (Gas development)
Larger amounts of I - disrupt the reaction. In this case, adding a few drops of Hg (NO 3 ) 2 solution causes the formation of HgI 4 2− . The latter has no effect on the described catalytic decomposition of iodine / azide.
literature
- Gerdes: Qualitative Inorganic Analysis, Springerverlag, 2nd edition, ISBN 978-3540670186
Web links
Wikibooks: Practical Course Inorganic Chemistry / Sulphide # Iodine-Azide Reaction - Learning and teaching materials