When copper carbonate (CuCO₃) is added to sodium hydroxide (NaOH), the following reaction occurs:

CuCO₃ (s) + 2NaOH (aq) → Cu(OH)₂ (s) + Na₂CO₃ (aq)

Here's what happens:

* Copper carbonate (CuCO₃) is a solid, blue-green compound.

* Sodium hydroxide (NaOH) is a strong base in aqueous solution.

* Copper hydroxide (Cu(OH)₂) is a solid, blue precipitate that forms.

* Sodium carbonate (Na₂CO₃) is a soluble salt that remains in solution.

In summary: The reaction produces a blue precipitate of copper hydroxide and a solution containing sodium carbonate.