What will happen, if zinc displaces gold in a chemical reaction?

Name the substance oxidised, reduced, oxidising agent and reducing agent in the following reaction:

$\mathrm{Ca}+{\mathrm{Cl}}_2\to {\mathrm{CaCl}}_2$

Name the substance oxidized, reduced, oxidizing agent and reducing agent in the following reaction:

$3{\mathrm{MnO}}_2+4\mathrm{Al}\to 3\mathrm{Mn}+2{\mathrm{Al}}_2{\mathrm{O}}_3$