Precipitation involves mixing or combining solutions that contain soluble ionic compounds to form an insoluble ionic compound by a reaction.
Sodium acetate and ammonium sulfate are both soluble ionic compounds, which implies that they exist as ions in aqueous solution.
<em><u>When they combine they form NH4CH3COOH and sodium sulfate, Na2SO4, which are both soluble salts, as all salts of ammonium and sodium are soluble.</u></em>
<em><u>Both ammonium acetate and sodium sulfate are soluble because there are no anions that can form an insoluble solid with NH4+ and Na+ cations. </u></em>