An aqueous solution of (NH4)2SO4 is acidic.
When ammonium sulfate ((NH4)2SO4) is dissolved in water, it dissociates into its ions: 2 NH4+ and SO4 2-. The ammonium ion (NH4+) is a weak acid and tends to donate a hydrogen ion (H+) to the water molecules, resulting in the formation of hydronium ions (H3O+). This increases the concentration of H+ ions in the solution and makes it acidic.
The chemical equation for the dissociation of ammonium sulfate in water is as follows:
(NH4)2SO4 + H2O → 2 NH4+ + SO4 2- + H2O
Therefore, among the options provided, the correct answer is acidic.