From the reaction of ammonia and sulfuric acid in aqueous solution
2nh3(aq)+h2so4(aq)→ (NH4)2SO4 + H2O
will be formed.Sulfuric acid is diprotic so is able to give up 2 H+ ions.
It is an acid-base neutralisation reaction forming ammonium sulphate as the salt.
2NH3 with H2SO4 reacts in a neutralization reaction to form salt water, with ammonium sulphate left behind to crystallize after evaporation.