Question

A bottle in lab is labeled [CoCl2.6H2O] = 0.71 M in 9.217 M HCl. If you determine [CoCl42-] to be 0.361 M at a particular temperature using absorbance measurements, what must be the value of [Co(H2O)62+] in the solution at that temperature?Express your response to three digits after the decimal.

Answer 1

Answer:

[Co(H₂O)₆]²⁺ = 0.361 M

Explanation:

[CoCl₂ . 6H₂O] + 2Cl⁻ → [CoCl₄]²⁻ + 6H₂O

[Co(H₂O)₆]²⁺ + 4Cl⁻ → [CoCl₄]²⁻ + 6H₂O

[CoCl₄]²⁻ = 0.361 M ∴ [Co(H₂O)₆]²⁺ = 0.361 M

The equation shows that the concentration of [Co(H₂O)₆]²⁺ should be equal to the concentration of [CoCl₄]²⁻.