Question

What happen when washing soda heated up

Answer 1

1) Washing soda is sodium carbonate Na2CO3, occurs as crystalline heptahydrate which on heating looses its water to form a white powder monohydrate. This process is called effloresces.

   Heat

Na2CO3.7H2O ---------------->  Na2CO3.H2O + 6 H2O

Sodium carbonate  <373 K   Sodium carbonate

heptahydrate   monohydrate(white powder)

Sodium carbonate monohydrate on further heating gives anhydrous sodium carbonate which is also called soda ash which is greyish white powder.

heat

Na2CO3.H2O  ------------->  Na2CO3  + H2O

   >373K  Sodium carbonate(anhydrous)

  greyish white powder

Answer 2

washing soda loses water when it s heated