A acid -base neutralization is a reaction that produces water and a salt. The acid should be strong as well as the base. Cacl2 comes from Ca(OH)2 and HCl- Ca(OH)2 is a strong base, hence CalCl2 is a salt from this rxn. NH3 is not a salt. BaF comes from strong Ba(OH)2 and weak HF, hence not a salt from this rxn. Na2SO4 comes from strong NaOH and strong H2SO4. The answer is BaF.