How would you distinguish between baking powder and washing soda by heating?
Baking soda (NaHCO3) gives carbon dioxide and water vapour on heating at very low temperature. The gas so formed turns lime water milky, which confirms the presence of carbon dioxide gas. When washing soda (Na2CO3) is heated it does not produce carbon dioxide even at high temperatures, but gives off its water of crystallisation to become anhydrous salt.
