Question

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

NCERT Class X
Science - Exemplar Problems

Chapter_Acids, Bases and Salts

Answer 1

Baking soda (NaHCO3) on heating produces carbon dioxide (CO2), which extinguishes a burning matchstick.

But washing soda (Na2CO3.10H2O) on heating does not produce any such gas, thus, it has no effect on burning matchstick.

Answer 2

Answer:

Baking powder will release carbon dioxide whereas washing soda will not.

Explanation:

• Upon heating baking powder ($NaHCO_{3}$), carbon dioxide is evolved, which extinguishes a lighted splint. The other two products are sodium carbonate and water.

$2NaHCO_{3} +$Δ→$Na_{2}CO_{3}+CO_{2}+H_{2}O$

• Upon heating washing soda ($NaHCO_{3}.10H_{2}O$), there is no production of carbon dioxide, instead, water is lost.

$NaHCO_{3}.10H_{2}O$+Δ→$NaHCO_{3}$+ $10H_{2}O$

• Even at high temperatures, $NaHCO_{3}.10H_{2}O$ does not give out carbon dioxide.