Notice
then that because hydrogen is more reactive than copper, it is able
to displace copper from its oxide, and copper is NOT able to displace
hydrogen from an acid.
–copper + hydrochloric acid (contains hydrogen) ¾® no reaction
On the
other hand, since hydrogen is less reaction than iron, it was not able
to displace iron from its oxide, and consequently iron is able to displace
hydrogen from an acid.
–iron + hydrochloric acid (contains hydrogen) ¾® iron chloride + hydrogen