On the net ionic equation of ammonium acetate and potassium sulfide
There are two compounds of ammonium acetate ($NH_ {4} CH_ {3} COO $) and potassium sulfide ($K_ {2} S $). When the two meet in solution, the chemical reaction can be explained by the net ionic equation.

The ionization of ammonium acetate in aqueous solution is ammonium ion ($NH_ {4 }^{+}$） and acetate ion ($CH_ {3} COO ^{-}$）， the ionization equation is: $NH_ {4} CH_ {3} COO\ rightarrow NH_ {4} ^ {+} + CH_ {3} COO ^ {-} $.

Potassium sulfide is ionized into potassium ions ($K ^ {+} $) and sulfur ions ($S ^ {2 - }$）， The ionization equation is: $K_ {2} S\ rightarrow 2K ^ {+} + S ^ {2 - }$。

When the two solutions are mixed, ammonium ions ($NH_ {4 }^{+}$） react with sulfur ions ($S ^ {2 -} $). Since the hydrolysis of ammonium ions makes the solution acidic, the hydrolysis of sulfur ions makes the solution alkaline, and the two promote each other's hydrolysis.

The hydrolysis reaction of ammonium ions is: $NH_ {4} ^ {+} + H_ {2} O\ rightleftharpoons NH_ {3}\ cdot H_ {2} O + H ^{+}$。

The hydrolysis reaction of sulfur ions is: $S ^ {2 - } + H_ {2} O\ rightleftharpoons HS ^ {-} + O H ^{-}$，$ HS ^ {-} + H_ {2} O\ rightleftharpoons H_ {2} S + O H ^{-}$。

Hydrogen ions combine with hydroxide ions to form water, which prompts the hydrolysis balance of ammonium ions and sulfur ions to shift to the right.

The net ion equation is: $2NH_ {4} ^ {+} + S ^ {2 - } + 2H_ {2} O\ rightleftharpoons 2NH_ {3}\ cdot H_ {2} O + H_ {2} S $.

This net ion equation clearly shows the nature of the reaction between ammonium acetate and potassium sulfide in solution, and the interaction between ions is on the paper, so that scholars understand the mechanism of the reaction.