# Write a net ionic equation for the reaction that occurs when excess hydroiodic acid and ammonium...

## Question:

Write a net ionic equation for the reaction that occurs when excess hydroiodic acid and ammonium sulfide are combined.

## Net Ionic Equation:

The chemical equation wherein the ions involved in the reaction are specified is referred to as the net ionic equation. As two aqueous solutions are mixed, this form of equation is obtained by the removal of spectator ions.

The given reaction takes place between excess hydroiodic acid and ammonium sulfide to form ammonium iodide and hydrogen sulfide. In a balanced chemical equation, the atoms on both the sides are equal. Therefore, the balanced molecular equation is shown below.

{eq}{\rm{2HI}}\left( {{\rm{aq}}} \right) + {\left( {{\rm{N}}{{\rm{H}}_{\rm{4}}}} \right)_{\rm{2}}}{\rm{S}}\left( {{\rm{aq}}} \right) \to 2{\rm{N}}{{\rm{H}}_{\rm{4}}}{\rm{I}}\left( {{\rm{aq}}} \right) + {{\rm{H}}_{\rm{2}}}{\rm{S}}\left( {\rm{g}} \right) {/eq}

The dissociation of hydroiodic acid and ammonium sulfide produces ions. The total ionic equation for the above reaction is shown below.

{eq}{\rm{2}}{{\rm{H}}^ + }\left( {{\rm{aq}}} \right) + 2{{\rm{I}}^ - }\left( {{\rm{aq}}} \right) + 2{\rm{NH}}_4^ + \left( {{\rm{aq}}} \right) + {{\rm{S}}^{2 - }}\left( {{\rm{aq}}} \right) \to 2{\rm{NH}}_4^ + \left( {{\rm{aq}}} \right) + 2{{\rm{I}}^ - }\left( {{\rm{aq}}} \right) + {{\rm{H}}_{\rm{2}}}{\rm{S}}\left( {\rm{g}} \right) {/eq}

In the total ionic equation, the common ions which are present on both the sides of the chemical equation that do not affect the identity of the equation are termed as the spectator ions. The spectator ions are removed from the net ionic equation.

Now, the net ionic equation is obtained by removing spectator ions as shown below.

{eq}{\rm{2}}{{\rm{H}}^ + }\left( {{\rm{aq}}} \right) + {{\rm{S}}^{2 - }}\left( {{\rm{aq}}} \right) \to + {{\rm{H}}_{\rm{2}}}{\rm{S}}\left( {\rm{g}} \right) {/eq}