Question

What is formed when Ammonium Iodide is treated with concentrated Sulphuric Acid?

Answer 1

The reaction of Ammonium Iodide with Sulphuric Acid

• When Ammonium Iodide (${\mathrm{NH}}_4\text{I}$) is treated with concentrated Sulphuric Acid (${\mathrm{H}}_2{\mathrm{SO}}_4$) then Iodine (${\mathrm{I}}_2$) gas, Hydrogen Sulphide, Ammonium Bisulphate, and water is produced.
• Iodine fumes are violet in colour.

$\underset{\mathrm{Ammonium}\mathrm{iodide}}{8{\mathrm{NH}}_4\mathrm{I}\left(\mathrm{s}\right)}+\underset{\mathrm{Sulphuric}\mathrm{acid}}{9{\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{l}\right)}\to \underset{\mathrm{Iodine}}{4{\mathrm{I}}_2\left(\mathrm{s}\right)}+\underset{\mathrm{Hydrogen}\mathrm{sulfide}}{{\mathrm{H}}_2\mathrm{S}\left(\mathrm{g}\right)}+\underset{\mathrm{Ammonium}\mathrm{bisulfite}}{8\left({\mathrm{NH}}_4\right){\mathrm{HSO}}_4}\left(\mathrm{aq}\right)+\underset{\mathrm{Water}}{4{\mathrm{H}}_2\mathrm{O}}$

So, when Ammonium Iodide is treated with concentrated Sulphuric Acid violet fumes of Iodine are formed.