NaOH + BaSO4 =

The reaction between sodium hydroxide (NaOH) and barium sulfate (BaSO₄) does not result in a significant chemical change because barium sulfate is a very insoluble salt. Therefore, when NaOH is added to a solution containing BaSO₄, no reaction occurs.

However, if barium sulfate is in a reaction medium where it could potentially dissolve, excess NaOH could lead to the formation of barium hydroxide (Ba(OH)₂), but this typically requires a specific range of conditions.

In summary, under normal circumstances, there is no significant chemical reaction between NaOH and BaSO₄, and the equation can be represented as:

\[ \text{NaOH} + \text{BaSO}_4 \rightarrow \text{no reaction} \]