Name the gas that liberates when an acid reacts with a metal. Illustrate your answer with an example giving the balanced equation for the reaction involved. How would you test gas evolved?
(i) Hydrogen gas (H2) is liberated when a metal reacts with an acid.
(ii) Reaction of zinc metal with sulphuric acid to give hydrogen gas.
(iii) Hydrogen gas can be tested by bringing a burning candle near the gas. It burns with a pop sound.