Blue litmus turns red in a solution, and bubbles form when chalk powder is added to it. What is the correct conclusion?
Answer and explanation
Correct answer: The solution is acidic and carbon dioxide formed from chalk
Two observations support the same conclusion. Blue litmus turning red indicates an acidic solution. Chalk is mainly calcium carbonate, CaCO₃. Acids react with carbonates to produce a salt, water, and carbon dioxide: acid + CaCO₃ → salt + H₂O + CO₂. The escaping CO₂ causes bubbles. Hydrogen and oxygen are not the expected gases in this reaction, so option A is correct.
Frequently asked questions
What is the correct answer to this question?
The solution is acidic and carbon dioxide formed from chalk
Why is this the correct answer?
Two observations support the same conclusion. Blue litmus turning red indicates an acidic solution. Chalk is mainly calcium carbonate, CaCO₃. Acids react with carbonates to produce a salt, water, and carbon dioxide: acid + CaCO₃ → salt + H₂O + CO₂. The escaping CO₂ causes bubbles. Hydrogen and oxygen are not the expected gases in this reaction, so option A is correct.
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.
