J. D. Lee Solutions for Chapter: Group 12 - the Zinc Group, Exercise 1: Exercise 1

Draw the structure of zinc blende. What is the coordination number of the ions and what is the radius ratio?

Explain how $\mathrm{Zn}$ is sacrificed in the extraction of $\mathrm{Cd}.$

Explain why a solution of zinc sulphate gives a white precipitate when added to an aqueous solution of ammonia, but not when added to an aqueous solution of ammonia containing ammonium chloride.

What is cadmium used for, how is it produced, and why are there problems of cadmium poisoning in the vicinity of zinc smelters?

List the main ways in which mercury compounds are discharged into the environment. Comment on the toxicity of inorganic and organic mercury compounds.

Give an account of disproportionation. Why is the mercury $\left(\mathrm{I}\right)$ ion written ${\mathrm{Hg}}_2^{2+},$ whilst the copper $\left(\mathrm{I}\right)$ ion is written ${\mathrm{Cu}}^{+}?$

What evidence is there that the mercury $\left(\mathrm{I}\right)$ ion is ${\mathrm{Hg}}_2^{2+}$ rather than ${\mathrm{Hg}}^{+}?$

When mercury is oxidized with a limited amount of oxidizing agent (i.e. an excess of $\mathrm{Hg}$) then ${\mathrm{Hg}}^{+}$compounds are formed. If there is an excess of oxidizing agent then ${\mathrm{Hg}}^{2+}$compounds are formed. Explain this.