really fast .. really tomorrow exam

We cannot store dilute HCl in those metal vessels which lie above hydrogen in the reactivity series. Such metals since they are more reactive will displace hydrogen from dilute HCl and release hydrogen gas and foem metal chloride.

We can store dilute HCl in a copper vessel and in vessels of other metals which lie below hydrogen in the reactivity series. SInce these metals like copper will be less reactive than hydrogen, they will not displace hydrogen from hydrochloric acid.