84. Specify which of the following equations represent oxidation- reduction reactions, and indicate the oxidizing agent, the re- ducing agent, the species being oxidized, and the species be- ing reduced. a. CH4(g) + H2O(g) âCO(g) + 3H2(g) b. 2AgNO3(aq) + Cu (s) â Cu (NO3)2(aq) + 2Ag (s) c. Zn(s) + 2HCl(aq)â ZnCl2(aq) + H2(g) d. 2H+ (aq) + 2CrO42-(aq) â Cr,072-(aq) + H2O(1)