Chapter 24

Explain the important distinction between each of the following pairs: (a) coordination number and oxidation number; (b) monodentate and polydentate ligands; (c) cis and trans isomers; (d) dextrorotatory and levorotatory compounds; (e) low-spin and highspin complexes.

The oxidation state of \(\mathrm{Ni}\) in the complex ion \(\left[\mathrm{Ni}(\mathrm{CN})_{4} \mathrm{I}\right]^{3-}\) is \((\mathrm{a})-3 ;(\mathrm{b})-2 ;(\mathrm{c}) 0 ;(\mathrm{d})+2 ;(\mathrm{e})+3\).

The coordination number of \(\mathrm{Pt}\) in the complex ion \(\left[\mathrm{PtCl}_{2}(\mathrm{en})_{2}\right]^{2+}\) is \((\mathrm{a}) 2 ;(\mathrm{b}) 3 ;(\mathrm{c}) 4 ;(\mathrm{d}) 5 ;(\mathrm{e}) 6\).

Of the following complex ions, the one that exhibits isomerism is (a) \(\left[\mathrm{Ag}\left(\mathrm{NH}_{3}\right)_{2}\right]^{+} ;\) (b) \(\left[\mathrm{CoNO}_{2}\left(\mathrm{NH}_{3}\right)_{5}\right]^{2+};\) \((\mathrm{c}) \quad\left[\mathrm{Pt}(\mathrm{en})\left(\mathrm{NH}_{3}\right)_{2}\right]^{2+};\) (d) \(\quad\left[\mathrm{CoCl}\left(\mathrm{NH}_{3}\right)_{5}\right]^{2+};\) (e) \(\left[\mathrm{PtCl}_{6}\right]^{2-}\).

Of the following complex ions, the one that is optically active is (a) \(\operatorname{cis}-\left[\operatorname{CoCl}_{2}(\text { en })_{2}\right]^{+} ;\) (b) \(\left[\operatorname{CoCl}_{2}\left(\mathrm{NH}_{3}\right)_{4}\right]^{+}\) (c) \(\left[\mathrm{CoCl}_{4}\left(\mathrm{NH}_{3}\right)_{2}\right]^{-} ;(\mathrm{d})\left[\mathrm{CuCl}_{4}\right]^{-}\).

The number of unpaired electrons in the complex ion \(\left[\operatorname{Cr}\left(\mathrm{NH}_{3}\right)_{6}\right]^{2+}\) is (a) \(5 ;(\mathrm{b}) 4 ;(\mathrm{c}) 3 ;(\mathrm{d}) 2 ;(\mathrm{e}) 1\).

Of the following, the one that is a Bronsted-Lowry acid is (a) \(\left[\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}\right]^{2+} ;\) (b) \(\left[\mathrm{FeCl}_{4}\right]^{-} ;\) (c) \(\left[\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}\) (d) \(\left[\mathrm{Zn}(\mathrm{OH})_{4}\right]^{-}\).

The most soluble of the following solids in \(\mathrm{NH}_{3}(\mathrm{aq})\) is (a) \(\mathrm{Ca}(\mathrm{OH})_{2} ;\) (b) \(\mathrm{Cu}(\mathrm{OH})_{2} ;\) (c) \(\mathrm{BaSO}_{4} ;\) (d) \(\mathrm{MgCO}_{3}\) (e) \(\overline{\mathrm{Fe}_{2} \mathrm{O}_{3}}\).

Name the following coordination compounds. Which one(s) exhibit(s) isomerism? Explain. (a) \(\left[\operatorname{CoBr}\left(\mathrm{NH}_{3}\right)_{5}\right] \mathrm{SO}_{4}\) (b) \(\left[\operatorname{Cr}\left(\mathrm{NH}_{3}\right)_{6}\right]\left[\mathrm{Co}(\mathrm{CN})_{6}\right]\) (c) \(\mathrm{Na}_{3}\left[\mathrm{Co}\left(\mathrm{NO}_{2}\right)_{6}\right]\) (d) \(\left[\mathrm{Co}(\mathrm{en})_{3}\right] \mathrm{Cl}_{3}\)

Write appropriate formulas for the following species. (a) dicyanoargentate(I) ion (b) triamminenitrito-N-platinum(II) ion (c) aquachlorobis(ethylenediamine)cobalt(III) ion (d) potassium hexacyanochromate(II)

Draw structures to represent these four complex ions: (a) \(\left[\mathrm{PtCl}_{4}\right]^{2-} ;\) (b) \(\left[\mathrm{FeCl}_{4}(\mathrm{en})\right]^{-} ;\) (c) \(\operatorname{cis}-\left[\mathrm{FeCl}_{2}(\mathrm{ox})(\mathrm{en})\right]^{-}\) (d) trans- \(\left[\mathrm{CrCl}(\mathrm{OH})\left(\mathrm{NH}_{3}\right)_{4}\right]^{+}\).

How many different structures are possible for each of the following complex ions? (a) \(\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)\left(\mathrm{NH}_{3}\right)_{5}\right]^{3+}\) (b) \(\left[\operatorname{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{2}\left(\mathrm{NH}_{3}\right)_{4}\right]^{3+}\) (c) \(\left[\operatorname{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{3}\left(\mathrm{NH}_{3}\right)_{3}\right]^{3+}\) (d) \(\left[\operatorname{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{4}\left(\mathrm{NH}_{3}\right)_{2}\right]^{3+}\)

Indicate what type of isomerism may be found in each of the following cases. If no isomerism is possible, so indicate. (a) \(\left[\mathrm{Zn}\left(\mathrm{NH}_{3}\right)_{4}\right]\left[\mathrm{CuCl}_{4}\right]\) (b) \(\left[\mathrm{Fe}(\mathrm{CN})_{5} \mathrm{SCN}\right]^{4-}\) (c) \(\left[\mathrm{NiCl}\left(\mathrm{NH}_{3}\right)_{5}\right]^{+}\) (d) \(\left[\mathrm{PtBrCl}_{2}(\mathrm{py})\right]\) (e) \(\left[\mathrm{Cr}(\mathrm{OH})_{3}\left(\mathrm{NH}_{3}\right)_{3}\right]^{-}\)

Indicate what type of isomerism may be found in each of the following cases. If no isomerism is possible, so indicate. (a) \(\left[\mathrm{Cr}(\mathrm{en})_{2} \mathrm{Br}_{2}\right]^{+}\) (b) \(\left[\operatorname{Co}(\text { ox })_{2} \operatorname{Br}(\text { SCN })\right]^{3-}\) (c) \(\left[\mathrm{NiCl}_{4}(\mathrm{en})\right]^{2-}\) (d) \([\mathrm{PtBrCl}(\text { ox })]^{-}\) (e) \(\left[\operatorname{Cr}(\text { Cl })_{3}(\text { det })\right],\) det is \(\mathrm{H}_{2} \mathrm{N}\left(\mathrm{CH}_{2}\right)_{2} \mathrm{NH}\left(\mathrm{CH}_{2}\right)_{2} \mathrm{NH}_{2}\)