Final answer:
Changes in temperature and chloride concentration can shift the equilibrium between [CoCl4]2- and [Co(H2O)6]2+, according to Le Châtelier's principle, but a catalyst does not shift the equilibrium.
Step-by-step explanation:
The equilibrium between [CoCl4]2- and [Co(H2O)6]2+ can be shifted by changes in temperature and chloride concentration. These factors are part of the different stresses that can affect a system at equilibrium according to Le Châtelier's principle, which states that an equilibrium system will shift in response to counteract a disturbance. Changes in concentration, including chloride concentration, will affect the equilibrium by changing the rate of the forward or reverse reaction, leading to a new equilibrium position. Similarly, temperature changes can also shift the equilibrium, as described by the Arrhenius equation. However, a catalyst, while it speeds up the attainment of equilibrium by increasing the rate of both the forward and reverse reactions, does not shift the equilibrium position.