Question

what happens when washing soda reacts with carbonate​

Answer 1

$\huge\bold\red{Hello}$

On heating sodium hydrogen carbonate decomposes to form sodium carbonate. This anhydrous sodium carbonate is known as soda ash. The preparation of Sodium Carbonate is also known as Solvay process. But before that calcium carbonate (limestone) was heated to release carbon dioxide.

Answer 2

Making Sodium Carbonate From Sodium Bicarbonate

Make Sodium Carbonate

Carbon dioxide and water will be given off, leaving dry sodium carbonate. This is the soda ash. The compound will readily absorb water, forming the hydrate (returning to baking soda). ... The decomposition reaction can be accelerated by heating the washing soda to 851 C (1124 K).