Why is zinc oxidized in this reaction?

Question

Zn(s) + 2HCl(aq) --> ZnCl2(aq) +H2(g)

Answer 1

Oxidation is the LOSS of electrons.  Looking at Zn in the equation, you see that on the left side of the equation, Zn(s) is elemental, which means it has an oxidation number of zero.  On the right side of the equation, Zn is in the form of ZnCl2, which means that Zn has an oxidation number of 2+ (because Cl is 1-).  Thus, Zn has gone from zero to 2+.  This means it LOST 2 electrons.  Thus, it has been oxidized.  If you are asking WHY is was oxidized, that has to do with the reduction and oxidation potentials of various elements.  The reduction potential for Zn is LESS than that for H⁺, so H+ is reduced and Zn is oxidized.