Zinc reacts with hydrochloric acid according to this reaction: Zn (s) + 2HCl (aq) → ZnCl2 (aq) + H2 (g) Which of the following will react the fastest? a. 2.0 gram lump of zinc in 0.10 M hydrochloric acid b. 2.0 gram sample of powdered zinc in 0.10 M hydrochloric acid c. 2.0 gram lump of zinc in 0.50 M hydrochloric acid d. 2.0 gram sample of powdered zinc in 0.50 M hydrochloric acid

To evaluate which system would be able to react faster, we look at the factor that could affect the reaction rate of the reaction of zinc and hydrochloric acid. First, we look at the concentrations or the amounts of the reactants. More reactant would mean that reaction rate is higher since collisions of the reactant molecules are likely to happen. We can disregard the amount of zinc since all choices have equal amount of zinc. Looking at the concentration of the hydrochloric acid, we have 0.10 M and 0.50 M. The latter would likely to have higher rate of reaction. Next, we look at the surface areas of the reactants. We neglect the effect of hydrochloric acid since they are all aqueous solution. Greater surface area would lead to higher rate since it would encourage more collisions. Powdered samples would have greater surface areas than lump samples. From the choices, most likely it would be 2.0 gram sample of powdered zinc in 0.50 M hydrochloric acid would have the higher reaction rate. Therefore, the answer is option D.