Question

When you buy washing soda from the market you will get it in powder form because

Answer 1

Washing soda or sodium carbonate (Na2CO)3 in its pure form is solid.

This is why you see it as powder (solid form).

Answer 2

Washing soda (Sodium Carbonate NA2CO3) in its common form, is a crystalline decahydrate. It easily converts to a white powder and hence available in its powder form, for ease of packing and usage.

Pure Sodium Carbonate is a white power which does not give out any smell and it absorbs moisture from the air. It is alkaline and used as a water softener in households.