Do you mean #"barium nitrate"# and #"sulfuric acid"#?
Explanation:
For #Ba(NO_3)_2(aq)# and #HCl(aq)# there would be no net macroscopic change. On the other hand, for #Ba(NO_3)_2(aq)# and #H_2SO_4(aq)#, a precipitate would form owing to the insolubility of #BaSO_4#: