On heating baking soda, the aqueous solution of the remaining solid is basic. What is the name of the remaining solid?
Answer and explanation
Correct answer: Sodium carbonate
Baking soda is sodium hydrogen carbonate, NaHCO3. On heating, it undergoes thermal decomposition: 2NaHCO3 → Na2CO3 + CO2 + H2O. The solid residue is therefore sodium carbonate, Na2CO3, and its aqueous solution is alkaline because carbonate ions undergo hydrolysis and produce hydroxide ions. Option A is correct. Sodium chloride is neutral, calcium sulphate is a different salt, and ammonium chloride gives an acidic solution.
Frequently asked questions
What is the correct answer to this question?
Sodium carbonate
Why is this the correct answer?
Baking soda is sodium hydrogen carbonate, NaHCO3. On heating, it undergoes thermal decomposition: 2NaHCO3 → Na2CO3 + CO2 + H2O. The solid residue is therefore sodium carbonate, Na2CO3, and its aqueous solution is alkaline because carbonate ions undergo hydrolysis and produce hydroxide ions. Option A is correct. Sodium chloride is neutral, calcium sulphate is a different salt, and ammonium chloride gives an acidic solution.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Acids, Bases, and Salts.
