a) They do not exhibit magnetic properties.
b) They form a definite crystalline structure.
c) They are always ionic in nature.
d) They have no color.
Answer: b) They form a definite crystalline structure.
Explanation: Coordination compounds form a definite crystalline
structure, often showing characteristic shapes and colors.
a) Na⁺
b) NH₃
c) Cl⁻
d) O₂
Answer: b) NH₃
Explanation: NH₃ is a neutral ligand that can donate a lone
pair of electrons to form a coordinate bond with a metal ion.
a) +2
b) +3
c) +4
d) +6
Answer: b) +3
Explanation: The oxidation state of Cr in [Cr(H₂O)₆]³⁺ is +3,
as the complex ion has no charge from the neutral water molecules.
a) The number of lone pairs around the central metal ion.
b) The number of ligands directly bonded to the central metal ion.
c) The number of electrons in the d-orbitals of the metal.
d) The number of bonds formed in the complex.
Answer: b) The number of ligands directly bonded to the central
metal ion.
Explanation: The coordination number refers to the number of
ligands directly attached to the central metal ion.
a) Cl⁻
b) H₂O
c) EDTA
d) NH₃
Answer: c) EDTA
Explanation: EDTA (ethylenediaminetetraacetic acid) is a
bidentate ligand because it can form two bonds with the metal ion.
a) Na₂[Fe(CN)₆]
b) Fe(CN)₆⁴⁻
c) [Fe(CN)₆]³⁻
d) Na[Fe(CN)₆]
Answer: b) Fe(CN)₆⁴⁻
Explanation: The complex formed is [Fe(CN)₆]⁴⁻ after
dissociation in water.
a) [Ni(CO)₄]
b) [Cu(NH₃)₄]²⁺
c) [Fe(CO)₅]
d) [Co(NH₃)₆]³⁺
Answer: a) [Ni(CO)₄]
Explanation: [Ni(CO)₄] has a coordination number of 4, as the
metal ion is surrounded by four CO ligands.
a) NH₃
b) EDTA
c) C₂O₄²⁻
d) H₂O
Answer: a) NH₃
Explanation: NH₃ is a monodentate ligand as it forms only one
bond with the central metal ion.
a) +2
b) +3
c) +4
d) +6
Answer: b) +3
Explanation: NH₃ is a neutral ligand, and the charge on the
complex ion is +3, so the oxidation state of Co is +3.
a) Transition metal complexes are always colorless.
b) Transition metal complexes exhibit colors due to d-d electronic transitions.
c) Transition metal complexes are colored only in the solid state.
d) Transition metal complexes do not show any color.
Answer: b) Transition metal complexes exhibit colors due to d-d
electronic transitions.
Explanation: The color of transition metal complexes arises
from the absorption of light during d-d transitions.
a) 2
b) 4
c) 6
d) 8
Answer: b) 4
Explanation: In [Ni(CO)₄], the central Ni atom is coordinated
to four CO ligands, hence the coordination number is 4.
a) It can form multiple bonds with the central metal atom.
b) It is a bidentate ligand.
c) It can form a single bond with the central metal atom.
d) It can form a stable complex with the metal ion.
Answer: c) It can form a single bond with the central metal
atom.
Explanation: A chelating ligand must form multiple bonds, not
just a single bond, with the metal ion.
a) Tetrahedral
b) Square planar
c) Octahedral
d) Linear
Answer: a) Tetrahedral
Explanation: [Ni(CO)₄] has a tetrahedral geometry as Ni is in
the zero oxidation state with four CO ligands.
a) [Co(NH₃)₆]³⁺
b) [Fe(CO)₅]
c) [Ni(CO)₄]
d) [Co(NH₃)₅Cl₂]²⁺
Answer: b) [Fe(CO)₅]
Explanation: [Fe(CO)₅] can exhibit linkage isomerism, where CO
can bind through the carbon or oxygen atom.
a) [Ni(CO)₄]
b) [PtCl₄]²⁻
c) [Co(NH₃)₆]³⁺
d) [Fe(CO)₅]
Answer: b) [PtCl₄]²⁻
Explanation: [PtCl₄]²⁻ exhibits square planar geometry, a
common geometry for metal complexes with d⁸ configuration.
a) 2
b) 4
c) 6
d) 8
Answer: b) 4
Explanation: [Cu(NH₃)₄]²⁺ has a coordination number of 4, with
four NH₃ molecules coordinated to the copper ion.
a) H₂O
b) NH₃
c) CN⁻
d) Cl⁻
Answer: a) H₂O
Explanation: H₂O is a hard Lewis acid, which prefers to
coordinate with hard metal ions.
a) Ligand field splitting
b) Charge transfer transitions
c) Crystal field stabilization
d) Ligand-to-metal charge transfer
Answer: a) Ligand field splitting
Explanation: The color of [Cr(H₂O)₆]³⁺ arises due to ligand
field splitting and the corresponding d-d electronic transitions.
a) +2
b) -2
c) +1
d) 0
Answer: a) +2
Explanation: The charge on the complex [CoCl₄]²⁻ is -2, with
cobalt in the +2 oxidation state.
a) [Fe(CO)₅]
b) [Ni(CO)₄]
c) [Cu(H₂O)₆]²⁺
d) [Cr(CO)₆]
Answer: c) [Cu(H₂O)₆]²⁺
Explanation: [Cu(H₂O)₆]²⁺ has an octahedral geometry because
Cu²⁺ is surrounded by six water molecules in a symmetrical arrangement.
a) The ligand binds through only one atom.
b) The ligand can form multiple bonds with the central metal atom.
c) The ligand is monodentate.
d) The ligand always forms an ionic bond with the metal.
Answer: b) The ligand can form multiple bonds with the central
metal atom.
Explanation: A chelating ligand is a bidentate or polydentate
ligand, which can form multiple bonds with the central metal atom.
a) Linkage isomerism
b) Geometrical isomerism
c) Optical isomerism
d) Ionization isomerism
Answer: b) Geometrical isomerism
Explanation: [Co(NH₃)₄Cl₂]⁺ shows geometrical isomerism due to
the different possible arrangements of the Cl⁻ ligands.
a) +2
b) +3
c) +6
d) +1
Answer: b) +3
Explanation: The +3 oxidation state of chromium is the most
stable in coordination compounds due to the relatively stable electronic
configuration.
a) It increases the crystal field splitting energy.
b) It decreases the crystal field splitting energy.
c) It results in high-spin complexes.
d) It results in weak magnetic properties.
Answer: a) It increases the crystal field splitting energy.
Explanation: Strong field ligands increase the crystal field
splitting energy, leading to low-spin complexes with paired electrons.
a) The central metal ion is always in the +1 oxidation state.
b) The ligands can only be anions.
c) The coordination number of the central metal ion is determined by the number
of bonds formed with ligands.
d) The ligands do not affect the magnetic properties of the complex.
Answer: c) The coordination number of the central metal ion is
determined by the number of bonds formed with ligands.
Explanation: The coordination number of the central metal ion
in a complex is determined by the number of bonds or coordination sites occupied
by ligands.
a) NH₃
b) H₂O
c) C₂O₄²⁻
d) CN⁻
Answer: c) C₂O₄²⁻
Explanation: C₂O₄²⁻ (oxalate ion) is a bidentate ligand, as it
can form two bonds with the metal ion.
a) [Ni(CO)₄]
b) [Fe(CO)₅]
c) [Cu(NH₃)₄]²⁺
d) [Cr(H₂O)₆]³⁺
Answer: d) [Cr(H₂O)₆]³⁺
Explanation: [Cr(H₂O)₆]³⁺ is paramagnetic due to the presence
of unpaired electrons in the d-orbitals of Cr³⁺.
a) 4
b) 2
c) 3
d) 5
Answer: b) 2
Explanation: In [Fe(CO)₅], CO is a strong field ligand, and the
metal-carbon bonds have a bond order of 2.
a) [NiCl₂(en)₂]
b) [CoCl₃(NH₃)₃]
c) [Cu(H₂O)₆]²⁺
d) [Cr(NH₃)₆]³⁺
Answer: a) [NiCl₂(en)₂]
Explanation: [NiCl₂(en)₂] shows optical isomerism because the
bidentate ligands can arrange themselves in such a way that non-superimposable
mirror images are formed.
a) Tetrahedral
b) Octahedral
c) Square planar
d) Linear
Answer: a) Tetrahedral
Explanation: [CoCl₄]²⁻ has a tetrahedral geometry with the
cobalt ion at the center and four chloride ions as ligands.
a) H₂O
b) NH₃
c) CN⁻
d) All of the above
Answer: d) All of the above
Explanation: All of H₂O, NH₃, and CN⁻ can act as ligands in
coordination chemistry.
a) It exhibits high-spin behavior.
b) It has a coordination number of 6.
c) It is a square planar complex.
d) It has an oxidation state of +2.
Answer: b) It has a coordination number of 6.
Explanation: In [Co(NH₃)₆]³⁺, the coordination number is 6,
with six NH₃ ligands surrounding the central Co³⁺ ion.
a) The nature of the ligands.
b) The oxidation state of the metal ion.
c) The geometry of the complex.
d) All of the above.
Answer: d) All of the above.
Explanation: The color of a coordination compound is influenced
by the nature of the ligands, the oxidation state of the metal, and the geometry
of the complex.
a) NH₃
b) CO
c) Cl⁻
d) CN⁻
Answer: c) Cl⁻
Explanation: Cl⁻ is a weak field ligand, leading to high-spin
complexes with fewer crystal field splitting effects.
a) [Cu(NH₃)₄]²⁺
b) [Ag(NH₃)₂]⁺
c) [Fe(CO)₅]
d) [Ni(CO)₄]
Answer: b) [Ag(NH₃)₂]⁺
Explanation: [Ag(NH₃)₂]⁺ is a 1:1 complex of silver ion with
two NH₃ ligands.
a) NH₃
b) C₂O₄²⁻
c) SCN⁻
d) H₂O
Answer: c) SCN⁻
Explanation: SCN⁻ (thiocyanate) is an ambidentate ligand
because it can bind through either the sulfur or nitrogen atom.
a) [Cu(NH₃)₄]²⁺
b) [Cu(NH₃)₆]²⁺
c) [Cu(NH₃)₄]
d) [Cu(NH₃)₂]²⁺
Answer: a) [Cu(NH₃)₄]²⁺
Explanation: In excess NH₃, Cu²⁺ forms the complex
[Cu(NH₃)₄]²⁺.
a) [Ni(CO)₄]
b) [Fe(CO)₅]
c) [PtCl₆]²⁻
d) [NiCl₄]²⁻
Answer: a) [Ni(CO)₄]
Explanation: [Ni(CO)₄] acts as a catalyst in the hydrogenation
of alkenes.
a) [Cr(NH₃)₆]³⁺
b) [Cu(NH₃)₄]²⁺
c) [PtCl₂(NH₃)₂]
d) [NiCl₄]²⁻
Answer: c) [PtCl₂(NH₃)₂]
Explanation: [PtCl₂(NH₃)₂] exhibits cis-trans isomerism due to
the square planar geometry of the complex.
a) It has a tetrahedral geometry.
b) It has a square planar geometry.
c) It is diamagnetic.
d) It has six ligands around the metal ion.
Answer: a) It has a tetrahedral geometry.
Explanation: [NiCl₄]²⁻ has a tetrahedral geometry with four
chloride ligands surrounding the nickel ion.
a) [Fe(CO)₅]
b) [Cu(NH₃)₄]²⁺
c) [Cr(H₂O)₆]³⁺
d) [Co(NH₃)₆]³⁺
Answer: c) [Cr(H₂O)₆]³⁺
Explanation: [Cr(H₂O)₆]³⁺ has unpaired electrons, making it
paramagnetic with high magnetic behavior.
a) EDTA
b) NH₃
c) C₂O₄²⁻
d) En
Answer: b) NH₃
Explanation: NH₃ (ammonia) is a monodentate ligand as it can
donate a lone pair from a single atom (nitrogen).
a) Tetrahedral
b) Square planar
c) Octahedral
d) Linear
Answer: a) Tetrahedral
Explanation: [Ni(CO)₄] has a tetrahedral geometry with carbon
monoxide as a ligand.
a) [CoCl₃(NH₃)₃]
b) [Cr(H₂O)₆]³⁺
c) [Ni(NH₃)₆]²⁺
d) [PtCl₃(NH₃)₃]
Answer: a) [CoCl₃(NH₃)₃]
Explanation: Ionization isomerism occurs when the exchange of
ligands between the inner coordination sphere and the counter ions results in
different ionic formulas.
a) It is a square planar complex.
b) It shows linkage isomerism.
c) It is a five-coordinate complex.
d) It has a tetrahedral geometry.
Answer: d) It has a tetrahedral geometry.
Explanation: [Mn(CO)₅Cl] has a tetrahedral geometry with
five-coordinate manganese.
a) [Cu(NH₃)₄]²⁺
b) [Ni(CO)₄]
c) [PtCl₄]²⁻
d) [Fe(CO)₅]
Answer: c) [PtCl₄]²⁻
Explanation: [PtCl₄]²⁻ exhibits square planar geometry due to
the d⁸ electronic configuration of Pt²⁺.
a) Fe²⁺
b) Fe³⁺
c) Co²⁺
d) Ni²⁺
Answer: b) Fe³⁺
Explanation: Fe³⁺ is more stable in coordination compounds
because it has a stable electron configuration and a higher charge density.
a) Ni
b) Cu
c) Fe
d) Cr
Answer: d) Cr
Explanation: Chromium can form coordination compounds in
oxidation states higher than +3, such as +6.
a) [Fe(CO)₅]
b) [Cr(NH₃)₆]³⁺
c) [CuCl₄]²⁻
d) [NiCl₄]²⁻
Answer: d) [NiCl₄]²⁻
Explanation: [NiCl₄]²⁻ is less stable due to the weak field
chloride ligands.
a) [Fe(CO)₆]²⁻
b) [Co(NH₃)₆]³⁺
c) [Cu(NH₃)₄]²⁺
d) [NiCl₄]²⁻
Answer: b) [Co(NH₃)₆]³⁺
Explanation: [Co(NH₃)₆]³⁺ has a low-spin configuration due to
the strong field nature of NH₃ ligands and the d⁶ configuration of Co³⁺.