Deck 24: Chemistry of Coordination Compounds

Question 1

Which one of the following species is a potential polydentate ligand (chelating agent)?

A) Cl^-
B) NH₃
C) H₂O
D) C₂O₄^2-
E) CN^-

Answer 1

C₂O₄^2-

Question 2

A complex of correctly written formula [Pt(NH₃)₃Br]Br·H₂O has which set of ligands in its inner coordination sphere?

A) 3 NH₃, 1 Br^- - , and 1 H₂O
B) 3 NH₃, 2 Br^- , and 1 H₂O
C) 3 NH₃ and 2 Br^-
D) 3 NH₃
E) 3 NH₃ and 1 Br^-

Answer 2

3 NH₃ and 1 Br^-

Question 3

What is the charge on the complex ion in Ca₂[Fe(CN)₆]?

A) 3-
B) 2+
C) 1-
D) 2-
E) 4-

Answer 3

4-

Question 4

What purpose would sodium tripolyphosphate serve in a detergent formulation?

A) to aid in removal of rust stains from surfaces and from clothes
B) to improve the flow characteristics of the detergent in the box
C) to aid in keeping the inside of washing machines clean and free from corrosion
D) to complex and hence sequester metal ions in hard water
E) to reduce bacterial growth in the detergent upon storage

Question 5

A ligand with a single donor atom is called .

A) bidentate
B) polydentate
C) a chelate
D) a chelon
E) monodentate

Question 6

Consider a complex in which manganese (III) is bonded to six identical ligands. Which one of the following ligands will result in the smallest value of O?

A) Cl^-
B) H₂O
C) F^-
D) NH₃
E) CN^-

Question 7

What form of hemoglobin is purplish- red?

A) oxyhemoglobin
B) deoxyhemoglobin

Question 8

What is the most common geometry found in four- coordinate complexes?

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

Question 9

Which one of the following geometries does not exhibit geometrical isomerism?

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

Question 10

What are the donor atoms in ferrichrome and how many of them are in one molecule?

A) Cr, 5
B) Fe, 4
C) N, 4
D) O, 6
E) S, 6

Question 11

Which one of the following is a strong- field ligand?

A) H₂O
B) NH₃
C) CN^-
D) Cl^-
E) F^-

Question 12

What metal is complexed in chlorophyll?

A) manganese
B) vanadium
C) magnesium
D) chromium
E) iron

Question 13

Which one of the following coordination compounds would be paramagnetic?

A) [Cd(H₂O)₆]SO₄
B) Na[CoCl₆] (low spin)
C) [Cu(H₂O)₄]Br
D) [Zn(NH₃)₄]Cl₂
E) K[FeCl₄] (low spin)

Question 14

Which of the following can form both high- and low- spin octahedral complexes?

A) Zn²⁺
B) Cu⁺
C) Cr³⁺
D) Cr²⁺
E) All of the above can form either high- or low- spin complexes.

Question 15

Which of the following will display optical isomerism?

A) octahedral Co(H₂NC₂H₄NH₂)₃³⁺
B) octahedral Co(NH₃)₆³⁺
C) octahedral Co(NH₃)₅Cl²⁺
D) square- planar Pt(H₂NC₂H₄NH₂)₂²⁺
E) square- planar Rh(CO)₂Cl₂^-

Question 16

How many bonds can ethylenediamine form to a metal ion?

A) 6
B) 4
C) 1
D) 3
E) 2

Question 17

Based on the crystal- field strengths F^- < CH₂CN < NH₃ < NO₂^- < CN^- , which Co(III) complex is most likely high- spin?

A) [Co(CN)₆]^3-
B) [Co(NO₂)₆]^3-
C) [Co(NH₃)₆]³⁺
D) [CoF₆]^3-
E) [Co(CH₃CN)₆]³⁺

Question 18

Based on entropy considerations alone, which homogeneous aqueous equilibrium would be expected to lie to the right?

A) AgI₂^- + 2Br^- AgBr₂^- + 2I^-
B) Fe(NH₃)₆²⁺ + C₂₀H₁₀N₄^2- 11ec835b_aed0_b9fc_b7a5_cf026f9e50f9_TB34225555_11Fe(NH₃)₂(C₂₀H₁₀N₄) + 4NH₃
C) CoCl₄²⁺ + 6H₂O 11ec835b_aed0_b9fc_b7a5_cf026f9e50f9_TB34225555_11Co(H₂O)₆²⁺ + 4Cl^-
D) Ni(H₂NC₂H₄NH₂)₃²⁺ + 6NH₃ 11ec835b_aed0_b9fc_b7a5_cf026f9e50f9_TB34225555_11Ni(NH₃)₆²⁺ + 3H₂NC₂H₄NH₂
E) Cu(NH₃)₄²⁺ + 6H₂O 11ec835b_aed0_b9fc_b7a5_cf026f9e50f9_TB34225555_11Cu( H₂O)₆²⁺ + 4NH₃

Question 19

Linkage isomerism would most likely occur when which of the following ligands is present?

A) Cl^-
B) PF₃
C) H₂O
D) NH₃
E) NCS^-

Question 20

What are the donor atoms in a porphine molecule?

A) F
B) O
C) S
D) N
E) Br

Question 21

Which complex below has 2 unpaired electrons?

A) square- planar [Ni(CN)₄]^2-
B) tetrahedral [CoCl₄]^2-
C) octahedral [Ni(NH₃)₆]²⁺
D) low- spin octahedral [Fe(CN)₆]^3-
E) tetrahedral [FeI₄]^2-

Question 22

Complexes containing metals with d¹⁰ electron configurations are typically _.

A) blue
B) colorless
C) yellow
D) violet
E) green

Question 23

The chelate effect is best attributed to considerations of which type?

A) entropy
B) hydrogen bonding
C) enthalpy
D) resonance
E) hydration

Question 24

Which one of the following complexes can exhibit geometrical isomerism?

A) [Pt(NH₃)₂Cl₂] (square planar)
B) [Zn(NH₃)₂Cl₂] (tetrahedral)
C) [Cu(NH₃)₅Cl]²⁺ (octahedral)
D) [Cu(NH₃)₄]²⁺ (square planar)
E) All of the above can exhibit geometrical isomerism.

Question 25

Which one of the following species is paramagnetic?

A) Ag⁺
B) Zn
C) Ca
D) Cu⁺
E) Cr³⁺

Question 26

What is the purpose of adding EDTA to prepared foods?

A) to complex trace metal ions that catalyze decomposition reactions
B) to keep ions such as Ca²⁺ in solution so the foods look good
C) to complex iron(III) ions so they can catalyze protein decomposition on cooking
D) to aid in browning of the surface during cooking
E) to prevent dissolution of the container in the food when stored for long periods of time

Question 27

Which of the following complexes has a coordination number of 6?

A) [Pt(NH₃)₂Cl₂]
B) [Ag(NH₃)₂]⁺
C) [Cu(NH₃)₄]²⁺
D) [Co(en)₂Cl₂]⁺
E) None of these complexes has coordination number 6.

Question 28

A racemic mixture is

A) a mixture of an optically active species with an optically inactive species.
B) a mixture of metal ions and ligands in equilibrium.
C) an equal mixture of both enantiomers of an optically active species.
D) a mixture of structural isomers.
E) an equal mixture of cis- and trans- isomers.

Question 29

Changes in the coordination sphere of a complex compound may lead to changes in .

A) chemical properties
B) color
C) physical properties
D) stability
E) all of the above

Question 30

Which one of the following substances has three unpaired d electrons?

A) [Ag(NH₃)₂]⁺
B) [Zn(NH₃)₄]²⁺
C) [Cr(CN)₆]^3-
D) [V(H₂O)₆]⁴⁺
E) [Cu(NH₃)₄]²⁺

Question 31

Which one of the following ions cannot form both a high spin and a low spin octahedral complex ion?

A) Cr²⁺
B) Fe³⁺
C) Co²⁺
D) Cr³⁺
E) Mn³⁺

Question 32

How many ligands are there in the coordination sphere of [Co(en)₂Cl₂]⁺?

A) 4
B) 0
C) 1
D) 3
E) 6

Question 33

Does either or both cis- or trans- [Mn(en)₂Br₂] have optical isomers?

A) cis only
B) trans only
C) both cis and trans
D) neither cis nor trans
E) [Mn(en)₂Br₂] does not exhibit cis- trans- isomerism.

Question 34

Which one of the following is the correct formula for potassium diaquatetrachloromolybdate (III)?

A) K₃[Mo(H₂O)₂Cl₄]
B) K₂[Mo(H₂O)₂Cl₄]
C) K[Mo(H₂O)₂Cl₄]
D) K[Mo(H₂O)₂Cl₂]Cl₂
E) Mo[K(H₂O)₂]Cl₄

Question 35

What are the respective central- metal oxidation state, coordination number, and overall charge on the complex ion in

A) +1; 6; - 2
B) +2; 6; - 2
C) +2; 4; - 1
D) +3; 6; - 1
E) +3; 6; +1

Question 36

Which of the following cannot form both high- and low- spin octahedral complexes?

A) Mn²⁺
B) Co³⁺
C) V²⁺
D) Cr²⁺
E) All of the above can form both high- and low- spin complexes.

Question 37

Formation of a complex species of Mⁿ⁺ metal ion with ligands often .

A) "masks" original chemical properties of both the Mⁿ⁺ ion and the ligands
B) may cause changes in the ease with which Mⁿ⁺ is reduced or oxidized
C) alters original physical properties of Mⁿ⁺
D) reduces availability of the free Mⁿ⁺ ions in solution
E) all of the above

Question 38

Based on the crystal- field strengths Cl^- < F^- < H₂O < NH₃ < H₂NC₂H₄NH₂, which octahedral Ti(III) complex below has its d- d electronic transition at shortest wavelength?

A) [TiF₆]^3-
B) [TiCl₆]^3-
C) [Ti(NH₃)₆]³⁺
D) [Ti(H₂NC₂H₄NH₂)₃]³⁺
E) [Ti( H₂O)₆]³⁺

Question 39

Which one of the following complex ions will be paramagnetic?

A) [Zn(H₂O)₄]²⁺
B) [Co(H₂O)₆]³⁺ (low spin)
C) [Fe(H₂O)₆]³⁺ (low spin)
D) [Fe(H₂O)₆]²⁺ (low spin)
E) [Zn(NH₃)₄]²⁺

Question 40

In the compound, CaNa[Fe(CN)₆], what ligands are in the coordination sphere?

A) CN^-
B) H₂O
C) Na⁺
D) Ca²⁺
E) none of the above

Question 41

What is the coordination number of the iron atom in CaNa[Fe(CN)₆]?

Question 42

The most common coordination numbers are _ .

Question 43

Based on electron configuration, which is most likely colorless?

A) [Ni(NH₃)₆]²⁺
B) [Cd(NH₃)₄]²⁺
C) [Cu(NH₃)₄]²⁺
D) [Co(NH₃)₆]²⁺
E) [Cr(NH₃)₅Cl]²⁺

Question 44

Using the following abbreviated spectrochemical series, determine which complex ion is most likely to absorb light in the red region of the visible spectrum.

A) [Cu(H₂O)₄]²⁺
B) [CuCl₄]^2-
C) [Cu(CN)₄]^2-
D) [Cu(NH₃)₄]²⁺
E) not enough information given to determine

Question 45

Which of the following is not a chelating agent?

A) oxalate anion
B) ethylenediamine
C) EDTA
D) chloride anion
E) porphine

Question 46

Two compounds have the same formula and contain an SCN^- ligand. In one compound the SCN^- ligand is bonded to the metal atom via the N atom and in the other it is bonded via the S atom. These two compounds are examples of _ _ isomers.

Question 47

Which one of the following complexes would most likely have tetrahedral geometry?

A) [Fe(CN)₆]³
B) [Pt(NH₃)₂Cl₂]
C) [Cr(NH₃)₆]³⁺
D) [Co(H₂O)₆]²⁺
E) [NiCl₄]^2-

Question 48

Complexes containing metals with which one of the following electron configurations are usually colorless?

A) d¹
B) d¹⁰
C) d⁸
D) d²
E) d⁵

Question 49

Complexes containing metals with d⁰ electron configurations are typically colorless because

A) d electrons must be emitted by the complex in order for it to appear colored.
B) the empty d orbitals absorb all of the visible wavelengths.
C) there is no d electron that can be promoted via the absorption of visible light.
D) a complex must be charged to be colored.
E) there are no d electrons to form bonds to ligands.

Question 50

Coordination sphere isomers

A) have the same formula and coordination number.
B) have the same formula but different coordination numbers.
C) are the same as resonance structures.
D) have different formulas but the same coordination number.
E) have different formulas and different coordination numbers.

Question 51

List three of the seven transition metals required for human life.

Question 52

The cis geometric isomer of what compound is a powerful anti cancer agent ?

Question 53

Werner's theory of primary and secondary valences for transition metal complexes has given us the concepts of and .

Question 54

Name Na[Ru(H₂O)₂(C₂O₄)₂]

Question 55

Non superimposable isomers are isomers.

Question 56

The transport of iron into bacteria is facilitated by the formation of the complex
.

Question 57

Which of the following is a polydentate ligand?

A) oxalate ion
B) water
C) hydroxide ion
D) ammonia
E) chloride ion

Question 58

A compound that can occupy two coordination sites is a (an) .

Question 59

What is the oxidation state of the iron atom in CaNa[Fe(CN)₆]?

Question 60

Transition metal ions with empty valence orbitals act as .

Question 61

Trans- [Fe(H₂O)₂Cl₄]^2- must be .

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

Question 62

What is the oxidation number of cobalt in [Co(NH₃)₄F₂] ?

A) +1
B) +3
C) +6
D) +2
E) - 3

Question 63

Define the chelate effect.

Question 64

What is the coordination number of cobalt in [Co(NH₃)₅Cl](NO₃)₂ ?

A) 4
B) 2
C) 12
D) 6
E) 8

Question 65

A large difference in formation constant (K_f ) is a poly- versus monodentate ligand is called .

Question 66

Six- coordinate complexes generally have geometry.

Question 67

The "dentation " of a ligand is defined by _ _.

A) how many "dents" or "deceptions" there are in the coordination sphere of a complex species it forms
B) how many electron donor atoms it utilizes to form coordinate bonds to the central metal ion
C) how many metal ions it can sequester from solution
D) the total number of lone pairs of electrons it possesses
E) none of the above

Question 68

The coordination number of platinum in complexes is always _ .

A) 2
B) 4
C) 5
D) 3
E) 6

Question 69

How many d electrons are in the cobalt ion of K₃[Co(CN)₆] ?

A) 7
B) 5
C) 3
D) 4
E) 6

Question 70

The correct name for Na₃[CoF₆] is .

A) trisodium hexakisfluorocobalt(III)
B) sodium hexafluorocobaltate(IV)
C) trisodium hexakisfluorocobalt(II)
D) trisodium hexakisfluorocobalt(IV)
E) sodium hexafluorocobaltate(III)

Question 71

What is the oxidation state of chromium in [Cr(H₂O)₄Cl₂]⁺ ?

A) 0
B) - 3
C) - 2
D) +3
E) +2

Question 72

How can high- spin and low- spin transition metal complexes be distinguished from each other?

Question 73

Linkage isomerism can only occur .

A) with tetrahedral complexes
B) with ligands that have more than one possible donor atom
C) with cobalt complexes
D) with coordination number 6
E) in cis- isomers of octahedral complexes

Question 74

The complex [Zn(NH₃)₂Cl₂]²⁺ does not exhibit cis- trans- isomerism. The geometry of this complex must be .

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

Question 75

What is the oxidation number of the central metal in [Mo(H₂O)₅NO_3] Cl₂

Question 76

EDTA is - dantate ligand.

A) tetra
B) bi
C) tri
D) mono
E) hexa

Question 77

What transition metal is responsible for the color of topaz _?

A) manganese
B) iron
C) cobalt
D) gold
E) chromium

Question 78

The porphyrin compound that contrains Mg(II) is called .

Question 79

What transition metal is responsible for the color of ruby ?

A) titanium
B) chromium
C) gold
D) manganese
E) cobalt

Question 80

The coordination number for [Zn(H₂O)₃Cl]Cl is _ .

A) 5
B) 2
C) 1
D) 4
E) 6