Question

Consider this reaction: Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g).
Which combination of factors will affect the rate of the reaction?
temperature, concentration, and surface area

temperature and concentration only

concentration and surface area only

temperature and surface area only

Answer 1

Surface area is important for zero-order reactions, or catalyzed reactions such as in the activation of hydrogen in water molecules by metals, or biochemical enzyme-substrate reactions, etc. This reaction involves the oxidation-reduction of solid zinc by a strong acid to extract the metal into an aqueous solution. The temperature affects the reaction in many ways, such as the solubility of all reactants and products, as well as their kinetic energy, and therefore reaction rates. The effects of concentration can be considered by le Chatlier's principle. For metal oxidations, I would say surface area is important because it determines how much metal surface is available for oxidation by the HCL.