• question_answer 68) The metal that does not displace hydrogen from an acid is A)  Zn                B)  CaC)  Al                D)  Hg

Hg does not displace.${{H}_{2}}$forms acid, as it is less reactive than${{H}_{2}}$(lies below${{H}_{2}}$in electrochemical series) or it has more reduction potential than${{H}_{2}}$so it cannot reduce ${{H}^{+}}$to ${{H}_{2}}.$ Hence, the correct option is [d].