Which is the most suitable sequence to confirm the presence of carbonate ions in a sample?
Answer and explanation
Correct answer: Add dilute acid and pass the gas into lime water
The governing test for carbonate ions uses acidification followed by limewater confirmation. A carbonate reacts with a dilute acid to release carbon dioxide: CO₃²⁻ + 2H⁺ → CO₂ + H₂O. Passing this gas into limewater produces calcium carbonate, making it milky. Smelling, magnet testing, or dry litmus cannot confirm carbonate ions, so A is correct.
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What is the correct answer to this question?
Add dilute acid and pass the gas into lime water
Why is this the correct answer?
The governing test for carbonate ions uses acidification followed by limewater confirmation. A carbonate reacts with a dilute acid to release carbon dioxide: CO₃²⁻ + 2H⁺ → CO₂ + H₂O. Passing this gas into limewater produces calcium carbonate, making it milky. Smelling, magnet testing, or dry litmus cannot confirm carbonate ions, so 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.
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