Metals on reaction with acids give out metal salt and hydrogen gas. When granules of zinc react with dilute hydrochloric acid it will produce zinc chloride and hydrogen gas. The reaction involved is:
Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g)
When a burning splinter is brought near to the beaker in which the reaction takes place then a pop sound is heard which confirms the presence of hydrogen gas.