Mostly, hydrogen gas is usually librated when an acid reacts with a metal.
First, take the two pieces of zinc granules in the test tube and dil H2SO4 to it. Shake it and pass the gas produced into a soap solution. After that, the bubbles of soap solution are formed. These soap bubbles contain hydrogen gas.
The CHEMICAL EQUATION is of reaction is
H2SO4 + Zn → ZnSO4 + H2
Identification of as testis, if we burning candle near the soap bubbles, it will burn with a soap sound.