Answer :
nothing happens
2NaNO₃(aq) + BaCl₂(aq) ⇄ 2NaCl(aq) + Ba(NO₃)₂(aq)
2Na⁺ + 2NO₃⁻ + Ba²⁺ + 2Cl⁻ ⇄ 2Na⁺ + 2Cl⁻ + Ba²⁺ + 2NO₃⁻
after evaporation of solution four salts crystallize
2NaNO₃(aq) + BaCl₂(aq) ⇄ 2NaCl(aq) + Ba(NO₃)₂(aq)
2Na⁺ + 2NO₃⁻ + Ba²⁺ + 2Cl⁻ ⇄ 2Na⁺ + 2Cl⁻ + Ba²⁺ + 2NO₃⁻
after evaporation of solution four salts crystallize