Which gas is usually liberated when an acid reacts with a metal? Illustrate with an example. How will you test for the presence of this gas?

Dear Student

When an acid react with a metal it liberates hydrogen gas.
E.g., Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g)
To test the presence of H2gas, bring a burning splinter near the mouth of the test tube where H2gas is released, the match stick bums with a pop sound.

​​​Thanks