Zinc metal reacts with hydrochloric acid to produce hydrogen gas
CHEMISTRY · Single correct · A Level · Chemistry · Kinetics · Kinetics
Problem
Zinc metal reacts with hydrochloric acid to produce hydrogen gas.
Experiment | Zinc form | Surface area (relative) | [HCl] (M)
A | Ribbon | 1 | 2.0
B | Powder | 50 | 1.0
In the laboratory, Experiment B is observed to proceed faster than Experiment A. Which of the following best explains this observation?
(a) The lower acid concentration in Experiment B lowers the activation energy of the reaction, so it proceeds faster.
(b) Hydrogen gas formed in Experiment B adsorbs on the zinc and serves as a catalyst, accelerating the reaction rate.
(c) The powdered zinc in Experiment B supplies a greatly increased surface area, leading to many more effective collisions with acid despite the lower concentration.
(d) The larger surface area of powdered zinc shifts the reaction equilibrium toward products according to Le Châtelier’s principle, increasing the reaction rate.