How is the gas formed in the reaction of an acid with hydrogen carbonate confirmed?
Answer and explanation
Correct answer: By turning lime water milky
An acid reacts with a hydrogen carbonate to form a salt, water, and carbon dioxide: acid + hydrogen carbonate → salt + H₂O + CO₂. Passing the gas through limewater produces insoluble calcium carbonate, making the limewater milky. A pop sound is the test for hydrogen, while litmus and phenolphthalein indicate acidity or basicity rather than confirming this gas. Therefore option A is correct.
Frequently asked questions
What is the correct answer to this question?
By turning lime water milky
Why is this the correct answer?
An acid reacts with a hydrogen carbonate to form a salt, water, and carbon dioxide: acid + hydrogen carbonate → salt + H₂O + CO₂. Passing the gas through limewater produces insoluble calcium carbonate, making the limewater milky. A pop sound is the test for hydrogen, while litmus and phenolphthalein indicate acidity or basicity rather than confirming this gas. Therefore 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.
