Deck 18: The Colorful Chemistry of Metals

Question 1

Identify the Lewis acid in the following reaction: PH₃(g) + H⁺(g)  PH₄⁺(g)

A) PH₃
B) H⁺
C) PH₄⁺
D) None of these is an acid.
E) All of these are acids.

Answer 1

H⁺

Question 2

What do you predict for the geometry of Ti(H₂O)₆³⁺?

A) octahedral
B) tetrahedral
C) square planar
D) trigonal bipyramidal
E) square pyramidal

Answer 2

octahedral

Question 3

A Lewis base is any species capable of __________ an electron pair.

A) accepting
B) donating
C) creating
D) neutralizing
E) gaining

Answer 3

donating

Question 4

The complex ion Fe(H₂O)₆³⁺ has 5 unpaired electrons in 3d-orbitals. Given this information, which iron orbitals would you expect to be hybridized and used to form the coordinate covalent bonds with water?

A) 4s, 4p, and 4d
B) 3s and 3p
C) 3s, 3p, and 3d
D) 4s, 4p, and 3d
E) 4s and 4p

Question 5

A coordinate covalent bond forms when __________

A) a chemical species donates one electron to another species to form a covalent bond.
B) a chemical species donates a pair of electrons to another species to form a covalent bond.
C) a chemical species accepts one electron from another species to form a covalent bond.
D) a chemical species accepts an electron and becomes an anion.
E) a chemical species accepts a pair of electrons and becomes an anion.

Question 6

Determine the molar concentration of Cl^- ions in a 1.00 M solution of AgCl₂^- with no excess silver ions. Given: K_f = 2.5  10⁵ for AgCl₂^-.

A) 0.020 M
B) 0.0040 M
C) 3.2  10^-2 M
D) 2.5  10^-2 M
E) 2.5  10⁵ M

Question 7

What is the shape of Zn(OH)₄^2-?

A) triangular pyramid
B) tetrahedral
C) octahedral
D) square pyramid
E) T-shaped

Question 8

What is the shape of the complex ion CoF₆^3-?

A) square pyramidal
B) octahedral
C) tetrahedral
D) trigonal bipyramidal
E) square planar

Question 9

A ligand is any __________ forming a coordinate bond to a metal cation.

A) Lewis acid
B) ion
C) Lewis base
D) organic compound
E) species

Question 10

In the following reaction, which species is the Lewis base? Cu²⁺ + NH₃  Cu(NH₃)²⁺

A) Cu²⁺
B) NH₃
C) [Cu(NH₃)]²⁺
D) None of these is a base.
E) All of these are bases.

Question 11

When NF₃ reacts with BF₃ to form F₃NBF₃,

A) a coordinate covalent bond is formed.
B) an ionic bond is formed.
C) the bond is formed by sharing an electron from NF₃ and an electron from BF₃.
D) a complex ion is formed.
E) a covalent bond is formed.

Question 12

A Lewis acid is any species capable of __________ an electron pair.

A) accepting
B) donating
C) creating
D) neutralizing
E) losing

Question 13

A Lewis base is __________

A) an electron-pair acceptor.
B) an electron-pair donor.
C) a proton donor
D) a proton acceptor.
E) never viewed also as a Brønsted-Lowry base.

Question 14

In the following reaction, which species is the Lewis acid? Cu²⁺ + NH₃  Cu(NH₃)²⁺

A) Cu²⁺
B) NH₃
C) [Cu(NH₃)]²⁺
D) None of these is an acid.
E) All of these are acids.

Question 15

A Lewis acid is __________

A) a proton donor.
B) a proton acceptor.
C) an electron-pair donor.
D) an electron-pair acceptor.
E) is never viewed also as a Brønsted-Lowry acid.

Question 16

Which of the following species is a Lewis base?

A) H⁺
B) Cs⁺
C) NF₃
D) NF₄⁺
E) NH₄⁺

Question 17

What would you predict for the hybridization of the Zn orbitals, based on the tetrahedral geometry of Zn(OH)₄^2-?

A) sp³d²
B) sp³
C) sp²d
D) sp³d
E) p²d²

Question 18

What is the molar concentration of Ag⁺(aq) in a 1.00 M solution of Ag(NH₃)₂⁺ with no excess ammonia? Given: K_f = 1.70  10⁷ for Ag(NH₃)₂⁺.

A) 2.45  10^-3 M
B) 3.09  10^-3 M
C) 2.42  10^-4 M
D) 1.47  10^-8 M
E) 1.70  10^-8 M

Question 19

Identify the Lewis base in the following reaction: PH₃(g) + H⁺(g)  PH₄⁺(g)

A) PH₃
B) H⁺
C) PH₄⁺
D) None of these is a base.
E) All of these are bases.

Question 20

Determine the molar concentration of Ag⁺(aq) ions in a 1.00 M solution of AgCl₂⁺ with no excess chloride. Given: K_f = 2.50  10⁵ for AgCl₂^-.

A) 2.52  10^-2 M
B) 1.26  10^-2 M
C) 0.0100 M
D) 0.0020 M
E) 2.50  10⁵ M

Question 21

Oxalic acid is a dicarboxylic acid with the structure HOOCCOOH. How many coordination sites does the ion (OOCCOO)^2- have?

A) 2
B) 3
C) 4
D) 1
E) 5

Question 22

Complex ions with different ligands have different colors because the ligands __________

A) are different colors.
B) affect the energy levels of the lone-pair electrons on the metal.
C) have different energies for their bonding electrons.
D) affect the energy levels of the metal d orbitals.
E) have different energies for their lone-pair electrons.

Question 23

Which of the following is a chelation agent?

A) EDTA
B) Cl^-
C) NH₂
D) SCN^-
E) CN^-

Question 24

The reaction Cr(NH₃)₆³⁺(aq) + 3 en(aq)  Cr(en)₃³⁺(aq) + 6 NH₃(aq)
Where en represents ethylenediamine, has a small value for the enthalpy change, H_rxn, yet the equilibrium constant for this reaction is large because __________

A) the reaction rate is fast.
B) the entropy change is large and positive.
C) the enthalpy change is large enough to matter.
D) the entropy change is large and negative.
E) the equilibrium constant does not depend on the enthalpy change.

Question 25

Which of the following statements is/are correct? A large negative free-energy change for a reaction means that __________
(I) the equilibrium constant for the reaction is large.
(II) the equilibrium constant for the reaction is small.
(III) the reaction greatly favors formation of the products.
(IV) only a small amount of product is produced at equilibrium.

A) I only
B) II only
C) both I and III
D) both I and IV
E) both II and IV

Question 26

Which atoms on EDTA bond to metal ions?

A) carbon and oxygen
B) carbon and nitrogen
C) oxygen and nitrogen
D) nitrogen and hydrogen
E) oxygen and hydrogen

Question 27

Which of the following statements is/are correct? A large equilibrium constant means that __________
(I) the free-energy change for the reaction is large and negative.
(II) the free-energy change for the reaction is large and positive.
(III) the reaction greatly favors formation of the products.
(IV) only a small amount of product is produced at equilibrium.

A) I only
B) II only
C) both I and III
D) both II and IV
E) both II and III

Question 28

Ethylenediamine is an example of a __________ ligand.

A) tridentate
B) hexadentate
C) bidentate
D) pentadentate
E) hydrocarbon

Question 29

What is the equilibrium concentration of Cu⁺(aq) in a solution that is 0.0200 M solution in CuNO₃ and 0.450 M HCl(aq)? Given: Cu⁺(aq) + 3Cl^-(aq)  CuCl₃^2- K_f = 5  10⁵

A) 1.0  10^-7 M
B) 6.7  10^-7 M
C) 4.4  10^-7 M
D) 5.0  10^-7 M
E) 5.0  10⁵ M

Question 30

How many chelation sites and donor groups does EDTA have?

A) 2
B) 10
C) 6
D) 4
E) 5

Question 31

Hydrated transition metal ions produce solutions that are __________

A) acidic.
B) basic.
C) neutral.
D) strongly basic.
E) strongly acidic.

Question 32

The reaction Cr(NH₃)₆³⁺(aq) + 3en(aq)  Cr(en)₃³⁺(aq) + 6 NH₃(aq)
Where en represents ethylenediamine, has a small value for the enthalpy change, H_rxn, yet the free-energy change is large because __________

A) the reaction rate is fast.
B) the entropy change is large and positive.
C) the enthalpy change is large enough to matter.
D) the entropy change is large and negative.
E) ethylene diamine has amino groups that are stronger bases than ammonia.

Question 33

When a molecule of ethylenediamine replaces two molecules of NH₃ in Co(NH₃)₆³⁺, the entropy of the system __________

A) increases.
B) decreases.
C) remains the same.
D) cannot be determined.
E) is irrelevant.

Question 34

What will be the equilibrium concentration of silver(I) ion in an aqueous solution originally containing 0.00100 M Ag⁺ and 0.500 M 1,10-phenanthroline?
Ag⁺(aq) + 2phen  [Ag(phen)₂]⁺ K_f = 1.2  10¹²
[Ag (phen)₂]⁺

A) 9  10^-7 M
B) 8  10^-13 M
C) 6  10^-6 M
D) 3.4  10^-15 M
E) 1.2  10^-12 M

Question 35

Calculate the equilibrium concentration of Zn²⁺(aq) in a solution that is 0.0125 M Zn(NO₃)₂ and 0.600 M NH₃. Given: Zn²⁺(aq) + 4 NH₃(aq)  Zn(NH₃)₄²⁺(aq) K_f = 2.9  10⁹

A) 7.8  10^-12 M
B) 4.7  10^-11 M
C) 1.5  10^-8 M
D) 2.5  10^-9 M
E) 2.9  10⁹ M

Question 36

For the reaction: Fe(H₂O)₆³⁺ + H₂O( )  Fe(H₂O)₅(OH)²⁺ + H₃O⁺(aq)
Fe(H₂O)₆³⁺ is a(n) __________ and water is a(n) __________

A) acid; base.
B) base; acid.
C) acid; catalyst.
D) catalyst; base.
E) Lewis base, Lewis acid.

Question 37

Which of the following is a polydentate ligand?

A) NH₃
B) OH^-
C) H₂O
D) diethylenetriamine
E) CN^-

Question 38

EDTA is an example of a __________ ligand.

A) tridentate
B) hexadentate
C) tetradentate
D) pentadentate
E) hydrocarbon

Question 39

The greater affinity of metal ions for polydentate ligands than for monodentate ligands is known as the __________ effect.

A) dentate
B) ligand
C) chelate
D) Lewis base
E) Lewis acid

Question 40

What is the equilibrium concentration of Cl^-(aq) in a solution that is 0.0200 M solution in CuNO₃ and 0.450 M HCl(aq)? Given: Cu⁺(aq) + 3 Cl^-(aq)  CuCl₃^2- K_f = 5  10⁵

A) 0.450 M
B) 2.0  10^-6 M
C) 0.390 M
D) 0.430 M
E) 5  10⁵ M

Question 41

As the value of the crystal field splitting, _o, increases from one complex ion to another, __________.

A) the wavelength of absorbed light increases.
B) the wavelength of absorbed light decreases.
C) the number of d electrons increases.
D) the number of d electrons decreases.
E) the color of the solution shifts from red towards blue.

Question 42

Co(NH₃)₆³⁺(aq) absorbs light in the blue region of the spectrum. The color of a solution containing this ion is __________

A) blue.
B) blue-violet.
C) violet.
D) yellow-orange.
E) red.

Question 43

Which of the following complexes has the largest crystal field splitting of the d orbitals?

A) CoF₆^3-
B) Co(CN)₆^3-
C) CoBr₆^3-
D) Co(H₂O)₆³⁺
E) CoI₆^3-

Question 44

When the five 3d orbitals on a metal ion experience an octahedral field in a complex, they split into __________ energy levels.

A) two
B) three
C) four
D) five
E) six

Question 45

Which d orbital(s) is/are highest in energy in a tetrahedral complex?

A) d_z²
B) d_xy, d_xz, and d_yz
C) d_z² and d_x² - _y²
D) d_x² - _y²
E) d_xy and d_xz

Question 46

In a tetrahedral crystal field, __________

A) d_xy, d_xz, and d_yz are lower in energy than d_x² - _y² and d_z².
B) d_x² - _y² and d_z² are lower in energy than d_xy, d_xz, and d_yz.
C) d_xy, d_xz, d_yz, d_x² - _y², and d_z² all have different energies.
D) d_xy, d_xz, d_yz, d_x² - _y², and d_z² all have the same energy.
E) d_xy, d_xz, and d_yz have the same energy, and d_x² - _y² and d_z² have different energies.

Question 47

Which of the following ligands will cause the smallest crystal field splitting of the d orbitals in an octahedral complex?

A) H₂O
B) Br^-
C) NH₃
D) CN^-
E) I^-

Question 48

Transition metal ions often absorb visible light in promoting electrons from a ground state to an excited state. Why doesn't aluminum(III) ion have this property?

A) It does, and this fact accounts for the color of some gemstones.
B) Aluminum(III) has a noble gas configuration-that of argon.
C) Aluminum(III) has a noble gas configuration-that of neon.
D) Aluminum(III) has a filled d subshell.
E) The crystal field splitting of the d orbitals in aluminum(III) is very large.

Question 49

The d_xy, d_xz, and d_yz orbitals are lower in energy than the d_z² and d_x² - _y² orbitals in an octahedral complex because these three orbitals __________

A) do not point directly at ligands.
B) point directly at ligands.
C) occupy larger volumes than the other two orbitals.
D) are in the same plane and repel one another.
E) occupy smaller volumes than the other two orbitals.

Question 50

A transition metal complex ion with octahedral geometry has a value of 4.4  10^-19 J for the crystal field splitting, _o. What is the wavelength for the absorption maximum, _max for this complex ion?

A) 5.0  10^-15 nm
B) 452 nm
C) 4.5  10^-16 nm
D) 524 mm
E) 637 nm

Question 51

A solution containing the ion CoF₆^3- has an absorption maximum at _max = 680 nm. The color of this solution is __________

A) red.
B) green.
C) blue.
D) orange.
E) violet.

Question 52

CoF₆^3- absorbs light in the red region of the spectrum, while Co(NH₃)₆³⁺ absorbs light on the blue region of the spectrum. This difference means that __________

A) the splitting of the d orbitals of the two complexes is nearly identical.
B) the value of the crystal field splitting is very small for both complexes.
C) the crystal field splitting is larger for the ammonia complex than for the fluoride complex.
D) the d_z² and d_x² - _y² orbitals are higher in energy than the d_xy, d_xz, and d_yz orbitals in CoF₆^3- and just the opposite splitting order for Co(NH₃)₆³⁺.
E) the d_z² and d_x² - _y² orbitals are lower in energy than the d_xy, d_xz, and d_yz orbitals in CoF₆^3- and just the opposite splitting order for Co(NH₃)₆³⁺.

Question 53

Which statement describing the splitting of metal d-orbitals in an octahedral field is not correct?

A) The d orbitals are split into two energy levels.
B) One energy level is three-fold degenerate.
C) One energy level is two-fold degenerate.
D) The d_xy, d_xz, and d_yz orbitals have the lowest energy.
E) Photons cannot produce electronic transitions from one energy level to another.

Question 54

Crystal field theory describes __________

A) how ligands cause the metal d orbitals to have different energies.
B) the covalent bonding in transition metal complexes.
C) how d orbitals change their shapes when ligands are present.
D) how metal s, p, and d orbitals are hybridized to bond with ligands.
E) the molecular orbitals that describe the bonding in transition metal complexes.

Question 55

Which 3d orbitals have a higher energy in an octahedral field?

A) d_xy and d_xz
B) d_z² and d_yz
C) d_z² and d_x² - _y²
D) d_x² - _y² and d_xz
E) d_xy, d_xz, and d_yz

Question 56

Which of the following complexes has the smallest crystal field splitting of the d orbitals?

A) CoF₆^3-
B) Co(CN)₆^3-
C) CoBr₆^3-
D) Co(H₂O)₆³⁺
E) CoI₆^3-

Question 57

Transition metals with __________ tend to form square planar complexes.

A) d⁸ and d⁹ configurations
B) d¹ and d² configurations
C) half-filled d orbitals
D) high spin
E) no d electrons

Question 58

Which of the following ligands will cause the largest crystal field splitting of the d orbitals in an octahedral complex?

A) H₂O
B) Br^-
C) NH₃
D) CN^-
E) I^-

Question 59

Given that the observed absorption maximum for the complex ion CoF₆^3- in solution is _max = 700 nm, what is the value of the crystal field splitting, _o?

A) 2.8  10^-19 J
B) 2.8  10^-28 J
C) 7.2  10³⁰ J
D) 3.2  10^-36 J
E) 7.2  10^-19 J

Question 60

The d_z² and d_x² - _y² orbitals are higher in energy than the d_xy, d_xz, and d_yz orbitals in an octahedral complex because these two orbitals __________

A) do not point directly at ligands.
B) point directly at ligands.
C) occupy larger volumes than the other three orbitals.
D) are in the same plane and repel one another.
E) occupy smaller volumes than the other three orbitals.

Question 61

What is the correct name for the following compound?

A) cis-diamminedichloroplatinum(II)
B) trans-diamminedichloroplatinum(III)
C) trans-diamminedichloroplatinum(II)
D) trans-dichlorodiammineplatinum(II)
E) cis-diamminedichloroplatinum(III)

Question 62

The correct name for the compound [Fe(NH₃)₅H₂O](NO₃)₂ is __________

A) pentammineaquairon(II) nitrate.
B) pentammineaquairon(III) nitrate.
C) pentammineaquaferrate(II) nitrate.
D) aquapentammineiron(II) nitrate.
E) pentamineaquadinitroiron(III).

Question 63

What is the correct formula for sodium tetracyanodihydroxovanadate(II)?

A) Na₂[V(CN)₄(OH)₂]
B) Na₃[V(CN)₄(OH)₂]
C) Na₄[V(CN)₄(OH)₂]
D) Na[V(CN)₄(OH)₂]
E) Na₃[V(CN)₄(OH)]

Question 64

The correct name for K₂[CuCl₄] is __________

A) potassium copper chloride.
B) potassium tetrachlorocuprate(II).
C) dipotassium chlorocuprate(II).
D) potassium tetrachlorocopper(II).
E) dipotassium tetrachlorocopper(II).

Question 65

How many d electrons are there in the chromium(III) ion?

A) 0
B) 3
C) 4
D) 5
E) 2

Question 66

The correct formula for ammonium tetracyanoplatinate(II) is __________

A) (NH₃)₂[Pt(CN)₄].
B) (NH₄)₂[Pt(CN)₄].
C) (NH₄)₂Pt(CN)₄.
D) (NH₄)₂[Pt(CN)₆].
E) NH₄[Pt(CN)₄].

Question 67

What is the correct formula for hexamminecobalt(III) nitrite?

A) [Co(NH₃)₆](NO₃)₃
B) Co(NH₃)₆(NO₂)₃
C) [Co(NH₃)₆](NO₂)₃
D) [Co(NH₃)₆](NO₂)₂
E) [Co(NH₃)₆](NO₃)₂

Question 68

Which of the following species most likely would be expected to be in a high-spin state?

A) Co(CN)₆^3-
B) Co(H₂O)₆³⁺
C) CoF₆^3-
D) Mn(CN)₆^4-
E) Co(NO₂)₆^3-

Question 69

The correct name for [Co(NH₃)₆][Cr(CN)₆] is __________

A) cobaltammine chromiumcyanide.
B) hexamminecobalt(III) hexacyanochromate (II).
C) hexamminecobaltate(III) hexacyanochromium(III).
D) hexamminecobalt(III) hexacyanochromate(III).
E) hexamminecobalt(II) hexacyanochromate(II).

Question 70

Which of the following metal ions can only have one spin state regardless of the ligand in an octahedral complex?

A) Cu²⁺
B) Co³⁺
C) Co²⁺
D) Mn²⁺
E) Mn³⁺

Question 71

How many stereoisomers are there for the compound [Fe(NH₃)₄(Cl₂)]NO₃?

A) 1
B) 2
C) 3
D) 4
E) 0

Question 72

The correct name for [Co(NH₃)₅Cl]Cl₂ is __________

A) pentamminechlorocobalt(III) chloride.
B) pentamminechlorocobalt(II) chloride.
C) chloropentamminecobalt(III) chloride.
D) pentamminechlorocobaltate(III) chloride.
E) pentamminedichlorocobalt(III).

Question 73

A strong crystal field produces a large value for the crystal field splitting, _o, while a weak crystal field produces a small crystal field splitting. Which would be more likely to put a metal ion in a high-spin configuration?

A) strong field
B) weak field
C) left field
D) right field
E) center field

Question 74

What is the correct name for the following compound?

A) trans-tetramminedichlorochromium(II)
B) cis-tetramminedichlorochromium(II)
C) cis-triamminedichlorochromium(II)
D) cis-tetramminechlorochromium(II)
E) cis-tetramminedichlorochromium(III)

Question 75

Which of the following transition metal ions would have the greater _o value when the same ligand was bound to the ions?

A) Co³⁺
B) Rh³⁺
C) Ir³⁺
D) They have the same _o value.

Question 76

Which of the following metal ions could be found in both high-spin and low-spin configurations in octahedral complex ions?

A) Zn(II)
B) Cu(II)
C) Co(II)
D) V(II)
E) Ti(II)

Question 77

The correct name for the complex ion [Co(NH₃)₅Cl]²⁺ is __________

A) pentamminechlorocobalt(III).
B) pentamminechlorocobalt(II).
C) chloropentamminecobalt(III).
D) pentamminechlorocobaltate(III).
E) pentamminechlorocobalt.

Question 78

Paramagnetic substances are attracted to magnetic fields. A set of synthetic mineral crystals was prepared with different metal ions substituted into the identical octahedral site in the lattice. If each crystal contained exactly the same number of the indicated metal ion, which would have the greatest attraction to a magnetic field?

A) Mn(II), high spin
B) Fe(II), high spin
C) Co(II), high spin
D) Ni(II), high spin
E) Cu(II), high spin

Question 79

How many unpaired electrons are there in the octahedral complex ion, Mn(CN)₆^4-?

A) 1
B) 2
C) 4
D) 5
E) 3

Question 80

The correct formula for the complex ion tetracyanoplatinate(II) is __________

A) [Pt(CN)₄²⁺].
B) [Pt(CN)₄]^2-.
C) Pt(CN)₄.
D) [Pt₂(CN)₄].
E) 4[Pt(CN)]⁺.