Question

[Co(H₂O)6]2+(aq) + 4Cl-(aq) D [CoCl₄]₂-(aq) + 6H₂O(l)

According to the equilibrium equation, which ion(s) do you have after the solid was diluted? Explain how you know the identity of the ion(s) present.

Answer 1

Upon diluting cobalt(II) chloride hexahydrate, the ions present are predominantly [Co(H2O)6]2+ and Cl-, with the potential formation of [CoCl4]2- depending on the chloride concentration.

Step-by-step explanation:

According to the equilibrium equation:

[Co(H₂O)6]2+(aq) + 4Cl-(aq) ⇌ [CoCl₄]2-(aq) + 6H₂O(l)

When the solid [Co(H₂O)6]Cl₂ is diluted in water, it dissociates into [Co(H₂O)6]2+ and Cl- ions. At equilibrium, the reaction can shift to form [CoCl₄]2- and water. The ions present after diluting the solid would primarily be [Co(H₂O)6]2+ and Cl-, with the possibility of some [CoCl₄]2- ions if excess chloride is present. The presence of these ions can be confirmed by analyzing the color of the solution, which changes from pink (for the [Co(H₂O)6]2+ ion) to blue (for the [CoCl₄]2- ion) as equilibrium shifts to the right in the presence of more chloride ions.