The gas from an acid-metal reaction is collected in soap bubbles and burns with a pop sound. What does this confirm?
Answer and explanation
Correct answer: Presence of hydrogen gas
The governing concept is the characteristic test for hydrogen. When a reactive metal reacts with an acid, hydrogen gas is commonly released, for example: Zn + 2HCl → ZnCl₂ + H₂. Hydrogen is highly combustible and, on bringing a flame near the collected gas, burns rapidly with a distinct pop sound. Carbon dioxide would extinguish a flame, while nitrogen is not combustible. Therefore, option A is correct.
Frequently asked questions
What is the correct answer to this question?
Presence of hydrogen gas
Why is this the correct answer?
The governing concept is the characteristic test for hydrogen. When a reactive metal reacts with an acid, hydrogen gas is commonly released, for example: Zn + 2HCl → ZnCl₂ + H₂. Hydrogen is highly combustible and, on bringing a flame near the collected gas, burns rapidly with a distinct pop sound. Carbon dioxide would extinguish a flame, while nitrogen is not combustible. 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.
