The compound that dissociates to produce the ions SO4^-2 (aq) and NH4+ IS (NH4)2SO4 (s).
(NH4)2SO4 is an ionic compound that dissociates itself upon its addition to the solvet to form a solution. When it is in the solution it forms ions.
The dissociation of ammonium sulfate forms 2 moles of ammonium ions (NH4+) and 1 mole of sulfate ion (SO4^2-).
That is; (NH4)2SO4 = 2 NH4+ + SO4^-2
