A student added acid to a metal carbonate and passed the gas through lime water. What is the correct observation?
Answer and explanation
Correct answer: Lime water will turn milky
This experiment demonstrates the characteristic test for carbon dioxide. A metal carbonate reacts with an acid to produce a salt, water and CO₂. When the gas is bubbled through lime water, it reacts with calcium hydroxide and forms insoluble calcium carbonate, making the solution appear milky: CO₂ + Ca(OH)₂ → CaCO₃ + H₂O. The colour changes in B and C are unsupported, while D ignores gas formation. Hence A is correct.
Frequently asked questions
What is the correct answer to this question?
Lime water will turn milky
Why is this the correct answer?
This experiment demonstrates the characteristic test for carbon dioxide. A metal carbonate reacts with an acid to produce a salt, water and CO₂. When the gas is bubbled through lime water, it reacts with calcium hydroxide and forms insoluble calcium carbonate, making the solution appear milky: CO₂ + Ca(OH)₂ → CaCO₃ + H₂O. The colour changes in B and C are unsupported, while D ignores gas formation. Hence 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.
Student feedback
Was this question useful?
👍 0 Helpful 👎 0 Not helpful
Yes 0% No 0%
0 responsesStudent Reviews
No published reviews yet.
