NCERT Exemplar Solutions Class 10 - Science - CHAPTER 2: Acids, Bases and Salts - Short Answer Questions
Question 37
Question. 37
37. How would you distinguish between baking powder and washing soda by heating?
Answer:
On heating baking soda (\(\mathrm{NaHCO_3}\)) decomposes to give sodium carbonate, water and carbon dioxide: \(\mathrm{2NaHCO_3 \xrightarrow{heat} Na_2CO_3 + H_2O + CO_2}\) (CO₂ will turn lime water milky). Washing soda (\(\mathrm{Na_2CO_3\cdot10H_2O}\)) on heating loses water but does not evolve CO₂. Thus evolution of CO₂ (turning lime water milky) identifies baking powder (NaHCO₃).
Detailed Answer with Explanation:
Steps: Heat samples; bubbling and CO₂ evolution (lime water test) indicates NaHCO₃; absence of CO₂ indicates washing soda.