To study the reaction between $\text{BaC}{l}_{\text{2}}{\text{\hspace{0.17em}and\hspace{0.17em}Na}}_{\text{2}}{\text{SO}}_{\text{4}}$, the two compounds are mixed in the form of

When $\text{BaC}{l}_2$ and ${\text{Na}}_{\text{2}}{\text{SO}}_4$ are mixed with each other in the aqueous state we will get a new salts.

$\text{BaC}{l}_2\left(\text{aq}\right)+{\text{Na}}_{\text{2}}{\text{SO}}_{\text{4}}\left(\text{aq}\right)\to {\text{BaSO}}_{\text{4}}\left(\text{s}\right)\downarrow +2\text{NaC}l\left(\text{aq}\right)$