Problem 13
When concentrated hydrochloric acid is added to a red solution containing the \(\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}^{2+}\) complex ion, the solution turns blue as the tetrahedral \(\mathrm{CoCl}_{4}^{2-}\) complex ion forms. Explain this color change.
Problem 14
Tetrahedral complexes of \(\mathrm{Co}^{2+}\) are quite common. Use a \(d\) -orbital splitting diagram to rationalize the stability of \(\mathrm{Co}^{2+}\) tetrahedral complex ions.
Problem 15
Which of the following ligands are capable of linkage isomerism? Explain your answer. $$\mathrm{SCN}^{-}, \mathrm{N}_{3}^{-}, \mathrm{NO}_{2}^{-}, \mathrm{NH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{NH}_{2}, \mathrm{OCN}^{-}, \mathrm{I}^{-}$$
Problem 16
Compounds of copper(II) are generally colored, but compounds of copper(I) are not. Explain. Would you expect \(\mathrm{Cd}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Cl}_{2}\) to be colored? Explain.
Problem 17
Compounds of \(\mathrm{Sc}^{3+}\) are not colored, but those of \(\mathrm{Ti}^{3+}\) and \(\mathrm{V}^{3+}\) are. Why?
Problem 18
What is the maximum number of unpaired \(d\) electrons that an octahedral transition metal complex ion can have? Predict a compound that would have this number of unpaired electrons.
Problem 19
Nickel can be purified by producing the volatile compound nickel tetracarbonyl. Nickel is the only metal that reacts with carbon monoxide at room temperature. Assuming this compound is overall neutral, what is the oxidation state of Ni in the compound? Deduce the formula of the compound.
Problem 20
Almost all metals in nature are found as ionic compounds in ores instead of being in the pure state. Why? What must be done to a sample of ore to obtain a metal substance that has desirable properties?
Problem 21
What causes high-altitude sickness, and what is high-altitude acclimatization?
Problem 22
Why are \(\mathrm{CN}^{-}\) and \(\mathrm{CO}\) toxic to humans?
