State as to why

a solution of Na₂CO₃ is alkaline?

A solution of Na₂CO₃ is alkaline because of the following reasons:

⇒ Na₂CO₃ is a salt of weak acid, carbonic acid (H₂CO₃) and a strong base, sodium hydroxide (NaOH)

⇒ Therefore, it undergoes hydrolysis to produce strong base and hence its aqueous solution is alkaline in nature.