Explain the properties of sodium carbonate.

Sodium carbonate is a white crystalline solid which exists as a decahydrate,$Na_{2}CO_{3} \cdot 10H_{2}O$. This is also called washing soda.
It is readily soluble in water.
On heating,the decahydrate loses its water of crystallization to form monohydrate.
Above $373 \ K$,the monohydrate becomes completely anhydrous and changes to a white powder called soda ash.
$Na_{2}CO_{3} \cdot 10H_{2}O \xrightarrow{375 \ K} Na_{2}CO_{3} \cdot H_{2}O + 9H_{2}O$
$Na_{2}CO_{3} \cdot H_{2}O \xrightarrow{>373 \ K} Na_{2}CO_{3} + H_{2}O$
The carbonate part of sodium carbonate gets hydrolysed by water to form an alkaline solution: $CO_{3}^{2-} + H_{2}O \rightarrow HCO_{3}^{-} + OH^{-}$