Why does copper generally not liberate hydrogen from dilute hydrochloric acid?
Answer and explanation
Correct answer: Copper is less reactive than hydrogen
The governing concept is the reactivity series. A metal liberates hydrogen from a dilute non-oxidising acid only when it is more reactive than hydrogen and can displace H⁺ ions. Copper lies below hydrogen in the series, so the displacement is not favourable under ordinary conditions and H₂ is generally not evolved. Hydrochloric acid does contain hydrogen, and copper is a solid metal, so the other choices are false.
Frequently asked questions
What is the correct answer to this question?
Copper is less reactive than hydrogen
Why is this the correct answer?
The governing concept is the reactivity series. A metal liberates hydrogen from a dilute non-oxidising acid only when it is more reactive than hydrogen and can displace H⁺ ions. Copper lies below hydrogen in the series, so the displacement is not favourable under ordinary conditions and H₂ is generally not evolved. Hydrochloric acid does contain hydrogen, and copper is a solid metal, so the other choices are false.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Metals and Non-metals. Topic: Reactivity series.
