Question

In a significant experiment performed many years ago, 5.6977 g of cadmium iodide in 44.69 g of water raised the boiling point 0.181 °C. What does this suggest about the nature of a solution of CdI2?

a) Cadmium iodide is a non-electrolyte.
b) Cadmium iodide is a weak electrolyte.
c) Cadmium iodide is a strong electrolyte.
d) Cadmium iodide does not dissolve in water.

Answer 1

The experiment that shows a 0.181 °C boiling point elevation from dissolving cadmium iodide in water suggests that CdI₂ is a strong electrolyte, as it dissociates completely into Cd²⁺ and 2I⁻ ions, which contribute to the boiling point elevation.

Step-by-step explanation:

The boiling point elevation observed in the experiment indicates that cadmium iodide CdI₂ is a strong electrolyte. This is because CdI₂, upon dissolving in water, dissociates completely into Cd²⁺ and 2I⁻ ions. The quantity of ions produced by the dissociation contributes to the boiling point elevation of the solution, which is higher than it would be if CdI₂ were a non-electrolyte or a weak electrolyte.

To confirm its nature as a strong electrolyte, we can compare the experimental boiling point elevation to the theoretical value calculated using the ebullioscopic constant for water and the molality of the solution. A strong electrolyte would produce a boiling point elevation consistent with the complete dissociation of its formula units into ions.