Which of the following equations does not represent an oxidation-reduction reaction
PCl_(3(g))+Cl_(2(g))->PCl_(3(g))
SO_(3(g))+CaO_((g))->CaSO_(4(s))
Mg_((s))+2HCl_((as))->MgCl_(2(as))+H_(2(g))
2Na_((s))+2H_(2)O_((l))->2NaOH_((ag))+H_(2(g))
CH_(4(g))+2O_(2(g))->CO_(2(g))+2H_(2)O_((g))