Question

How would you distinguish between baking powder and washing soda by heating?

Answer 1

The production of carbon dioxide is a characteristic difference observed during the heating of baking powder and washing soda. Baking powder, on heating, produces sodium carbonate, carbon dioxide gas, and water.

$2{\text{NaHCO}}_3\text{(s)}\stackrel{\text{Heat}}{\to }{\text{Na}}_2{\text{CO}}_3\text{(s)}+{\text{CO}}_2\text{(g)}+{\text{H}}_2\text{O}\text{(l)}$

Similarly, when washing soda ${\text{(Na}}_2{\text{CO}}_3)$ is heated, it does not produce carbon dioxide. It loses its water of crystallisation and becomes anhydrous.

${\text{Na}}_2{\text{CO}}_3\cdot 10{\text{H}}_2\text{O(s)}\to {\text{Na}}_2{\text{CO}}_3\text{(s)}+10{\text{H}}_2\text{O(l)}$