Chemistry

Paul Flowers, Klaus Theopold, Richard Langley

Chapter 19

Transition Metals and Coordination Chemistry - all with Video Answers

Educators

HC

Chapter Questions

Problem 1

Write the electron configurations for each of the following elements:
(a) Sc
(b) Ti
(c) Cr
(d) Fe
(e) Ru

Aadit Sharma

Aadit Sharma

Numerade Educator

Problem 2

Write the electron configurations for each of the following elements and its ions:
(a) $\mathrm{Ti}$
(b) $\mathrm{Ti}^{2+}$
(c) $\mathrm{Ti}^{3+}$
(d) $\mathrm{Ti}^{4+}$

Cecile Wang

Numerade Educator

Problem 3

Write the electron configurations for each of the following elements and its $3+$ ions:
(a) La
(b) Sm
(c) Lu

Aadit Sharma

Numerade Educator

Problem 4

Why are the lanthanoid elements not found in nature in their elemental forms?

Cecile Wang

Numerade Educator

Problem 5

Which of the following elements is most likely to be used to prepare La by the reduction of $\mathrm{La}_{2} \mathrm{O}_{3}: \mathrm{Al}, \mathrm{C},$ or $\mathrm{Fe} ?$ Why?

Aadit Sharma

Numerade Educator

Problem 6

Which of the following is the strongest oxidizing agent: $\mathrm{VO}_{4}^{3}, \quad \mathrm{CrO}_{4}^{2-},$ or $\mathrm{MnO}_{4}^{-} ?$

Cecile Wang

Numerade Educator

Problem 7

Which of the following elements is most likely to form an oxide with the formula $\mathrm{MO}_{3}: \mathrm{Zr}, \mathrm{Nb},$ or $\mathrm{Mo}$ ?

Aadit Sharma

Numerade Educator

Problem 8

The following reactions all occur in a blast furnace. Which of these are redox reactions?
(a) $3 \mathrm{Fe}_{2} \mathrm{O}_{3}(s)+\mathrm{CO}(g) \longrightarrow 2 \mathrm{Fe}_{3} \mathrm{O}_{4}(s)+\mathrm{CO}_{2}(g)$
(b) $\mathrm{Fe}_{3} \mathrm{O}_{4}(s)+\mathrm{CO}(g) \longrightarrow 3 \mathrm{FeO}(s)+\mathrm{CO}_{2}(g)$
(c) $\mathrm{FeO}(s)+\mathrm{CO}(g) \longrightarrow \mathrm{Fe}(l)+\mathrm{CO}_{2}(g)$
(d) $\mathrm{C}(s)+\mathrm{O}_{2}(g) \longrightarrow \mathrm{CO}_{2}(g)$
(e) $\mathrm{C}(s)+\mathrm{CO}_{2}(g) \longrightarrow 2 \mathrm{CO}(g)$
(f) $\mathrm{CaCO}_{3}(s) \longrightarrow \mathrm{CaO}(s)+\mathrm{CO}_{2}(g)$
(g) $\mathrm{CaO}(s)+\mathrm{SiO}_{2}(s) \longrightarrow \mathrm{CaSiO}_{3}(l)$

Cecile Wang

Numerade Educator

Problem 9

Why is the formation of slag useful during the smelting of iron?

Aadit Sharma

Numerade Educator

Problem 10

Would you expect an aqueous manganese(VII) oxide solution to have a pH greater or less than 7.0 ? Justify your answer.

Adriano Chikande

Adriano Chikande

Numerade Educator

Problem 11

Iron(II) can be oxidized to iron(III) by dichromate ion, which is reduced to chromium(III) in acid solution. A 2.5000-g sample of iron ore is dissolved and the iron converted into iron(II). Exactly $19.17 \mathrm{mL}$ of $0.0100 \mathrm{M}$ $\mathrm{Na}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$ is required in the titration. What percentage of the ore sample was iron?

Aadit Sharma

Numerade Educator

Problem 12

How many cubic feet of air at a pressure of 760 torr and $0^{\circ} \mathrm{C}$ is required per ton of $\mathrm{Fe}_{2} \mathrm{O}_{3}$ to convert that $\mathrm{Fe}_{2} \mathrm{O}_{3}$ into iron in a blast furnace? For this exercise, assume air is $19 \%$ oxygen by volume.

Cecile Wang

Numerade Educator

Problem 13

Find the potentials of the following electrochemical cell:
$$\mathrm{Cd}\left|\mathrm{Cd}^{2+}, M=0.10 \| \mathrm{Ni}^{2+}, M=0.50\right| \mathrm{Ni}$$

Aadit Sharma

Numerade Educator

Problem 14

A 2.5624-g sample of a pure solid alkali metal chloride is dissolved in water and treated with excess silver nitrate. The resulting precipitate, filtered and dried, weighs 3.03707 g. What was the percent by mass of chloride ion in the original compound? What is the identity of the salt?

Cecile Wang

Numerade Educator

Problem 15

The standard reduction potential for the reaction $\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}(a q)+\mathrm{e}^{-} \longrightarrow\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}(a q)$ is about 1.8 V. The reduction potential for the reaction $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{3+}(a q)+\mathrm{e}^{-} \longrightarrow\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{2+}(a q)$ is $+0.1 \mathrm{V}$. Calculate the cell potentials to show whether the complex ions, $\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}$ and/or $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{2+},$ can be oxidized to the corresponding cobalt(III) complex by oxygen.

Aadit Sharma

Numerade Educator

Problem 16

Predict the products of each of the following reactions. (Note: In addition to using the information in this chapter, also use the knowledge you have accumulated at this stage of your study, including information on the prediction of reaction products.)
(a) $\mathrm{MnCO}_{3}(s)+\mathrm{HI}(a q) \longrightarrow$
(b) $\operatorname{CoO}(s)+\mathrm{O}_{2}(g) \longrightarrow$
(c) $\operatorname{La}(s)+\mathrm{O}_{2}(g) \longrightarrow$
(d) $\mathrm{V}(s)+\mathrm{VCl}_{4}(s) \longrightarrow$
(e) $\operatorname{Co}(s)+x s F_{2}(g) \longrightarrow$
(f) $\operatorname{CrO}_{3}(s)+\operatorname{CsOH}(a q) \rightarrow$

Cecile Wang

Numerade Educator

Problem 17

Predict the products of each of the following reactions. (Note: In addition to using the information in this chapter, also use the knowledge you have accumulated at this stage of your study, including information on the prediction of reaction products.)
(a) $\operatorname{Fe}(s)+\mathrm{H}_{2} \mathrm{SO}_{4}(a q) \longrightarrow$
(b) $\mathrm{FeCl}_{3}(a q)+\mathrm{NaOH}(a q) \rightarrow$
(c) $\operatorname{Mn}(\mathrm{OH})_{2}(s)+\operatorname{HBr}(a q) \rightarrow$
(d) $\operatorname{Cr}(s)+\mathrm{O}_{2}(g) \longrightarrow$
(e) $\mathrm{Mn}_{2} \mathrm{O}_{3}(s)+\mathrm{HCl}(a q) \longrightarrow$
(f) $\operatorname{Ti}(s)+x s F_{2}(g) \rightarrow$

Temi Ajayi

Numerade Educator

Problem 18

Describe the electrolytic process for refining copper.

Rashmi Sinha

Numerade Educator

Problem 19

Predict the products of the following reactions and balance the equations.
(a) $\mathrm{Zn}$ is added to a solution of $\mathrm{Cr}_{2}\left(\mathrm{SO}_{4}\right)_{3}$ in acid.
(b) $\mathrm{FeCl}_{2}$ is added to a solution containing an excess of $\mathrm{Cr}_{2} \mathrm{O}_{7}{^2}{^-}$ in hydrochloric acid.
(c) $\mathrm{Cr}^{2+}$ is added to $\mathrm{Cr}_{2} \mathrm{O}_{7}{^3}{^-}$ in acid solution.
(d) Mn is heated with CrO $_{3}$
(e) CrO is added to $2 \mathrm{HNO}_{3}$ in water.
(f) $\mathrm{FeCl}_{3}$ is added to an aqueous solution of $\mathrm{NaOH}$.

Aadit Sharma

Numerade Educator

Problem 20

What is the gas produced when iron(II) sulfide is treated with a nonoxidizing acid?

Cecile Wang

Numerade Educator

Problem 21

Predict the products of each of the following reactions and then balance the chemical equations.
(a) Fe is heated in an atmosphere of steam.
(b) $\mathrm{NaOH}$ is added to a solution of $\mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{3}$
(c) $\mathrm{FeSO}_{4}$ is added to an acidic solution of $\mathrm{KMnO}_{4}$
(d) Fe is added to a dilute solution of $\mathrm{H}_{2} \mathrm{SO}_{4}$
(e) A solution of $\mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{2}$ and $\mathrm{HNO}_{3}$ is allowed to stand in a-
(f) $\mathrm{FeCO}_{3}$ is added to a solution of $\mathrm{HClO}_{4}$
(g) Fe is heated in air.

Aadit Sharma

Numerade Educator

Problem 22

Balance the following equations by oxidation-reduction methods; note that three elements change oxidation state. $\mathrm{Co}\left(\mathrm{NO}_{3}\right)_{2}(s) \longrightarrow \mathrm{Co}_{2} \mathrm{O}_{3}(s)+\mathrm{NO}_{2}(g)+\mathrm{O}_{2}(g)$

Rashmi Sinha

Numerade Educator

Problem 23

Dilute sodium cyanide solution is slowly dripped into a slowly stirred silver nitrate solution. A white precipitate forms temporarily but dissolves as the addition of sodium cyanide continues. Use chemical equations to explain this observation. Silver cyanide is similar to silver chloride in its solubility.

Aadit Sharma

Numerade Educator

Problem 24

Predict which will be more stable, $\left[\mathrm{CrO}_{4}\right]^{2-}$ or $\left[\mathrm{WO}_{4}\right]^{2-},$ and explain.

Elif Kucukefe

Numerade Educator

Problem 25

Give the oxidation state of the metal for each of the following oxides of the first transition series. (Hint: Oxides of formula $\mathrm{M}_{3} \mathrm{O}_{4}$ are examples of mixed valence compounds in which the metal ion is present in more than one oxidation state. It is possible to write these compound formulas in the equivalent format $\mathrm{MO} \cdot \mathrm{M}_{2} \mathrm{O}_{3},$ to permit estimation of the metal's two oxidation states.)
(a) $\mathrm{Sc}_{2} \mathrm{O}_{3}$
(b) $\mathrm{Ti} \mathrm{O}_{2}$
(c) $\mathrm{V}_{2} \mathrm{O}_{5}$
(d) $\mathrm{CrO}_{3}$
(e) $\mathrm{MnO}_{2}$
(f) $\mathrm{Fe}_{3} \mathrm{O}_{4}$
(g) $\mathrm{Co}_{3} \mathrm{O}_{4}$
(h) $\mathrm{NiO}$
(i) $\mathrm{Cu}_{2} \mathrm{O}$

Daniel Kyinakwa

Daniel Kyinakwa

Numerade Educator

Problem 26

Indicate the coordination number for the central metal atom in each of the following coordination compounds:
(a) $\left[\operatorname{Pt}\left(\mathrm{H}_{2} \mathrm{O}\right)_{2} \mathrm{Br}_{2}\right]$
(b) $\left[\operatorname{Pt}\left(\mathrm{NH}_{3}\right)(\mathrm{py})(\mathrm{Cl})(\mathrm{Br})\right]\left(\mathrm{py}=\text { pyridine }, \mathrm{C}_{5} \mathrm{H}_{5} \mathrm{N}\right)$
(c) $\left[\mathrm{Zn}\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Cl}_{2}\right]$
(d) $\left[\mathrm{Zn}\left(\mathrm{NH}_{3}\right)(\mathrm{py})(\mathrm{Cl})(\mathrm{Br})\right]$
(e) $\left[\mathrm{Ni}\left(\mathrm{H}_{2} \mathrm{O}\right)_{4} \mathrm{Cl}_{2}\right]$
(f) $\left[\mathrm{Fe}(\mathrm{en})_{2}(\mathrm{CN})_{2}\right]^{+}\left(\mathrm{en}=\text { ethylenediamine }, \mathrm{C}_{2} \mathrm{H}_{8} \mathrm{N}_{2}\right)$

Rashmi Sinha

Numerade Educator

Problem 27

Give the coordination numbers and write the formulas for each of the following, including all isomers where appropriate:
(a) tetrahydroxozincate(II) ion (tetrahedral)
(b) hexacyanopalladate(IV) ion
(c) dichloroaurate(I) ion (note that aurum is Latin for "gold")
(d) diamminedichloroplatinum(II)
(e) potassium diamminetetrachlorochromate(III)
(f) hexaamminecobalt(III) hexacyanochromate(III)
(g) dibromobis(ethylenediamine) cobalt(III) nitrate

Aadit Sharma

Numerade Educator

Problem 28

Give the coordination number for each metal ion in the following compounds:
(a) $\left[\mathrm{Co}\left(\mathrm{CO}_{3}\right)_{3}\right]^{3-}$ (note that $\mathrm{CO}_{3}{^2}{^-}$ is bidentate in this complex)
(b) $\left[\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}\right]^{2+}$
(c) $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Br}_{2}\right]_{2}\left(\mathrm{SO}_{4}\right)_{3}$
(d) $\left[\mathrm{Pt}\left(\mathrm{NH}_{3}\right)_{4}\right]\left[\mathrm{PtCl}_{4}\right]$
(e) $\left[\mathrm{Cr}(\mathrm{en})_{3}\right]\left(\mathrm{NO}_{3}\right)_{3}$
(f) $\left[\mathrm{Pd}\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Br}_{2}\right]$ (square planar)
(g) $\mathrm{K}_{3}\left[\mathrm{Cu}(\mathrm{Cl})_{5}\right]$
(h) $\left[\mathrm{Zn}\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Cl}_{2}\right]$

Daniel Kyinakwa

Daniel Kyinakwa

Numerade Educator

Problem 29

Sketch the structures of the following complexes. Indicate any cis, trans, and optical isomers.
(a) $\left[\operatorname{Pt}\left(\mathrm{H}_{2} \mathrm{O}\right)_{2} \mathrm{Br}_{2}\right]$ (square planar)
(b) $\left[\operatorname{Pt}\left(\mathrm{NH}_{3}\right)(\mathrm{py})(\mathrm{Cl})(\mathrm{Br})\right]$ (square planar, py $=$ pyridine, $\mathrm{C}_{5} \mathrm{H}_{5} \mathrm{N}$ )
(c) $\left[\mathrm{Zn}\left(\mathrm{NH}_{3}\right)_{3} \mathrm{Cl}\right]^{+}$ (tetrahedral)
(d) $\left[\operatorname{Pt}\left(\mathrm{NH}_{3}\right)_{3} \mathrm{Cl}\right]^{+}$ (square planar)
(e) $\left[\mathrm{Ni}\left(\mathrm{H}_{2} \mathrm{O}\right)_{4} \mathrm{Cl}_{2}\right]$
(f) $-\left[\mathrm{Co}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)_{2} \mathrm{Cl}_{2}\right]^{3-} \text { (note that } \mathrm{C}_{2} \mathrm{O}_{4}{^2}{^-} \text { is the bidentate oxalate ion, }-\mathrm{O}_{2} \mathrm{CCO}_{2}{^-} \text {) }$

Aadit Sharma

Numerade Educator

Problem 30

Draw diagrams for any cis, trans, and optical isomers that could exist for the following (en is ethylenediamine):
(a) $\left[\mathrm{Co}(\mathrm{en})_{2}\left(\mathrm{NO}_{2}\right) \mathrm{Cl}\right]^{+}$
(b) $\left[\mathrm{Co}(\mathrm{en})_{2} \mathrm{Cl}_{2}\right]^{+}$
(c) $\left[\mathrm{Pt}\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Cl}_{4}\right]$
(d) $\left[\mathrm{Cr}(\mathrm{en})_{3}\right]^{3+}$
(e) $\left[\operatorname{Pt}\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Cl}_{2}\right]$

Madi Sousa

Numerade Educator

Problem 31

Name each of the compounds or ions given in Exercise 19.28 , including the oxidation state of the metal.

Aadit Sharma

Numerade Educator

Problem 32

Name each of the compounds or ions given in Exercise 19.30 .

Aadit Sharma

Numerade Educator

Problem 33

Specify whether the following complexes have isomers.
(a) tetrahedral $\left[\mathrm{Ni}(\mathrm{CO})_{2}(\mathrm{Cl})_{2}\right]$
(b) trigonal bipyramidal $\left[\mathrm{Mn}(\mathrm{CO})_{4} \mathrm{NO}\right]$
(c) $\left[\operatorname{Pt}(\mathrm{en})_{2} \mathrm{Cl}_{2}\right] \mathrm{Cl}_{2}$

Aadit Sharma

Numerade Educator

Problem 34

Predict whether the carbonate ligand $\mathrm{CO}_{3}{^2}{^-}$ will coordinate to a metal center as a monodentate, bidentate, or tridentate ligand.

Rashmi Sinha

Numerade Educator

Problem 35

Draw the geometric, linkage, and ionization isomers for $\left[\mathrm{CoCl}_{5} \mathrm{CN}\right][\mathrm{CN}]$.

Aadit Sharma

Numerade Educator

Problem 36

Determine the number of unpaired electrons expected for $\left[\mathrm{Fe}\left(\mathrm{NO}_{2}\right)_{6}\right]^{3-}$ and for $\left[\mathrm{FeF}_{6}\right]^{3-}$ in terms of crystal field theory.

Daniel Kyinakwa

Daniel Kyinakwa

Numerade Educator

Problem 37

Draw the crystal field diagrams for $\left[\mathrm{Fe}\left(\mathrm{NO}_{2}\right)_{6}\right]^{4-}$ and $\left[\mathrm{FeF}_{6}\right]^{3-} .$ State whether each complex is high spin or low spin, paramagnetic or diamagnetic, and compare $\Delta_{\text {oct }}$ to $P$ for each complex.

HC

Hashim Choudhry

Numerade Educator

Problem 38

Give the oxidation state of the metal, number of $d$ electrons, and the number of unpaired electrons predicted for $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right] \mathrm{Cl}_{3}$

Daniel Kyinakwa

Daniel Kyinakwa

Numerade Educator

Problem 39

The solid anhydrous solid $\mathrm{CoCl}_{2}$ is blue in color. Because it readily absorbs water from the air, it is used as a humidity indicator to monitor if equipment (such as a cell phone) has been exposed to excessive levels of moisture. Predict what product is formed by this reaction, and how many unpaired electrons this complex will have.

Aadit Sharma

Numerade Educator

Problem 40

Is it possible for a complex of a metal in the transition series to have six unpaired electrons? Explain.

Rashmi Sinha

Numerade Educator

Problem 41

How many unpaired electrons are present in each of the following?
(a) $\left[\mathrm{CoF}_{6}\right]^{3-}$ (high spin)
(b) $\left[\mathrm{Mn}(\mathrm{CN})_{6}\right]^{3-}(\text { low spin })$
(c) $\left[\mathrm{Mn}(\mathrm{CN})_{6}\right]^{4-}(\text { low spin })$
(d) $\left[\mathrm{MnCl}_{6}\right]^{4-}$ (high spin)
(e) $\left[\mathrm{RhCl}_{6}\right]^{3-}$ (low spin)

Aadit Sharma

Numerade Educator

Problem 42

Explain how the diphosphate ion, $\left[\mathrm{O}_{3} \mathrm{P}-\mathrm{O}-\mathrm{PO}_{3}\right]^{4-}$, can function as a water softener that prevents the precipitation of $\mathrm{Fe}^{2+}$ as an insoluble iron salt.

Rashmi Sinha

Numerade Educator

Problem 43

For complexes of the same metal ion with no change in oxidation number, the stability increases as the number of electrons in the $t_{2 g}$ orbitals increases. Which complex in each of the following pairs of complexes is more stable?
(a) $\left[\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}$ or $\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{4-}$
(b) $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{3+}$ or $\left[\mathrm{CoF}_{6}\right]^{3-}$
(c) $\left[\mathrm{Mn}(\mathrm{CN})_{6}\right]^{4-}$ or $\left[\mathrm{MnCl}_{6}\right]^{4-}$

Aadit Sharma

Numerade Educator

Problem 44

Trimethylphosphine, $\mathrm{P}\left(\mathrm{CH}_{3}\right)_{3},$ can act as a ligand by donating the lone pair of electrons on the phosphorus atom. If trimethylphosphine is added to a solution of nickel(II) chloride in acetone, a blue compound that has a molecular mass of approximately $270 \mathrm{g}$ and contains $21.5 \% \mathrm{Ni}, 26.0 \% \mathrm{Cl}$ and $52.5 \% \mathrm{P}\left(\mathrm{CH}_{3}\right)_{3}$ can be isolated. This blue compound does not have any isomeric forms. What are the geometry and molecular formula of the blue compound?

Rashmi Sinha

Numerade Educator

Problem 45

Would you expect the complex $\left[\mathrm{Co}(\mathrm{en})_{3}\right] \mathrm{Cl}_{3}$ to have any unpaired electrons? Any isomers?

Aadit Sharma

Numerade Educator

Problem 46

Would you expect the $\mathrm{Mg}_{3}\left[\mathrm{Cr}(\mathrm{CN})_{6}\right]_{2}$ to be diamagnetic or paramagnetic? Explain your reasoning.

Rashmi Sinha

Numerade Educator

Problem 47

Would you expect salts of the gold(I) ion, $\mathrm{Au}^{+}$, to be colored? Explain.

Aadit Sharma

Numerade Educator

Problem 48

$\left[\mathrm{CuCl}_{4}\right]^{2-}$ is green. $\left[\mathrm{Cu}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}$ is blue. Which absorbs higher-energy photons? Which is predicted to have a larger crystal field splitting?

Rashmi Sinha

Numerade Educator