* Hydrolysis: When sodium carbonate dissolves in water, it undergoes hydrolysis. This means it reacts with water molecules to form hydroxide ions (OH⁻).

* Hydroxide ions: The presence of hydroxide ions in solution is what makes a substance basic.

* Carbonate ion: The carbonate ion (CO₃²⁻) is a weak base. It can accept protons (H⁺) from water molecules, further contributing to the basic nature of the solution.

Therefore, sodium carbonate solutions have a pH greater than 7, indicating that they are basic.