Question

When acids react with metal, which gas is liberated?

Answer 1

If an acid reacts with any metal, a salt and hydrogen gas will be formed.

Metal + Acid → Salt + Hydrogen gas

Answer 2

Hydrogen gas is usually liberated when an acid reacts with a metal.

 Take few pieces of zinc granules and add 5 ml of dilute H2SO4. Shake it and pass the gas produced into a soap solution. The bubbles of the soap solution are formed. These soap bubbles contain hydrogen gas.
H₂SO₄ + Zn → ZnSO₄ + H₂ ↑
We can test the evolved hydrogen gas by its burning with a pop sound when a candle is brought near the soap bubbles.