Metals replace hydrogen from dilute acids, whereas non-metals do not. Why?
Answer:
Hydrogen from dilute acids can only be replaced if electrons are supplied to H+ ions of the acid.
Metals have a tendency to lose electrons and hence they supply electrons, i.e., they are electron donors. That is why metals displace hydrogen from dilute acids.
On the other hand, non-metal is an electron acceptor. It cannot supply electrons to H+ and hence, it does not displace hydrogen from dilute acids.