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

Explanation

Baking soda is sodium hydrogen carbonate `(NaHCO_(3)).` Upon heating, it will evolve `CO_(2)` gas which upon passing through lime water, will make it milky.
`2NaHCO_(3)overset("heat")to Na_(2)CO_(3)+H_(2)O+CO_(2)`
Washing soda is sodium carbonate decahydrate `(Na_(2)CO_(3).10H_(2)O).` Upon heating, it will not evolve any gas.
`Na_(2)CO_(3).10H_(2)Ooverset("heat") to na_(2)CO_(3)+10H_(2)O`