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All questions of Coordination Compounds for NEET Exam

The correct IUPAC name of the complex Fe(C5H5)2 is _
  • a)
    Cyclopentadienyl iron (II)
  • b)
    Bis (cyclopentadienyl) iron (II)
  • c)
    Dicyclopentadiency ferrate (II) 
  • d)
    Ferrocene
Correct answer is option 'B'. Can you explain this answer?

Alok Mehta answered
The iron complex may be treated as cationic part, and C5H5- is a bidentate ligand therefore name can be assigned as follows “dicyclopentadienyl Iron (II) cation”.

A magnetic moment of 1.73 BM will be shown by one among the following
  • a)
    [Cu(NH3)4]2+
  • b)
    [Ni(CN)4]2–
  • c)
    TiCl4
  • d)
    [CoCl6]4–
Correct answer is option 'A'. Can you explain this answer?

Ritu Singh answered
The correct answer is Option A.
Electronic configuration of Cu2+  ion in [Cu(NH3)4]2+.
Cu2+ ion =[Ar]3d94s0.
∴Cu2+ ion has one unpaired electron.
Magnetic moment of [Cu(NH3)4]2+ (μ) = BM
where, n = no. of unpaired electrons

Whereas Ni2+ in [Ni(CN)4]2− , Ti4+ in TiCl4 and Co2+ ion [COCl6]4− has 2,0 and 3 unpaired electrons respectively.

Tollen’s reagent contains
  • a)
    AgOH
  • b)
    AgNO3
  • c)
    [Ag(NO3)2]+
  • d)
    [Ag(NH3)2]+
Correct answer is option 'B'. Can you explain this answer?

Akash Shah answered
Toilen’s reagent is ammoniacal silver nitrate solution. It is used to distinguish aldehydes and ketones, reducing and non-reducing sugars.

The hybrisation of Co in [Co(H2O)6]3+ is :
  • a)
    d2sp3
  • b)
    dsp2
  • c)
    dsp3
  • d)
    spd3
Correct answer is option 'A'. Can you explain this answer?

Rajeev Saxena answered
In this complex compound the total charge is +3 as H2O is a neutral compound so the oxidation state of cobalt is +3 and the electronic configuration of Co is 3d7 4s2. So, Co(+3)=4d6 and H2O is a weak ligand so there is no pairing of electron. So,4s 4p3 and 4d2 orbital make hybrid orbital to have a hybridization of d2sp3.

The complex potassium dicyanodioxalatonickelate (II) in solution produce....... ions.
    Correct answer is '5'. Can you explain this answer?

    Anaya Patel answered
    The structure of potassium dicyanodio xalatonickelate (II) is
    K4[Ni(CN)2(ox)2].
    K4[Ni(CN)2(ox)2] →  4K+ [Ni(CN)2(ox)2]- 
    This produce 5 ions in solution.

    Number of EDTA molecules required to form an octahedral complex.
      Correct answer is '1'. Can you explain this answer?

      Mira Sharma answered
      One EDTA (ethylenediaminetetraacetic acid) molecule is required to make an octahedral complex with Ca^2+ ion

      In the estimation of hardness of water, the reagent used is
      • a)
        hypo solution
      • b)
        KMnO4
      • c)
        EDTA solution
      • d)
        K2Cr2O7
      Correct answer is option 'C'. Can you explain this answer?

      Preeti Iyer answered
      The EDTA solution can then be used to determine the hardness of an unknown water sample. Since both EDTA and Ca2+ are colorless, it is necessary to use a special indicator to detect the end point of the titration.

      In the formation of complex entity, the central atom/ion acts as
      • a)
        Bronsted acid
      • b)
        Lewis base
      • c)
        Lewis acid
      • d)
        Bronsted base
      Correct answer is option 'C'. Can you explain this answer?

      Arka Das answered
      Explanation:

      In the formation of a complex entity, a central atom/ion acts as a Lewis acid. This can be explained as follows:

      Lewis Acid and Lewis Base:
      According to Lewis acid-base theory, a Lewis acid is a species that accepts a pair of electrons to form a coordinate covalent bond, while a Lewis base is a species that donates a pair of electrons to form a coordinate covalent bond.

      Formation of Complex Entity:
      A complex entity is formed by the coordination of a central atom/ion with one or more ligands. Ligands are molecules or ions that donate a pair of electrons to the central atom/ion to form a coordinate covalent bond.

      Role of Central Atom/Ion:
      In the formation of a complex entity, the central atom/ion acts as a Lewis acid because it accepts a pair of electrons from the ligands to form a coordinate covalent bond. The central atom/ion has an incomplete outer shell, which makes it electron deficient and thus able to accept electrons from other species.

      Examples:
      Some examples of complex entities and their central atom/ion are as follows:

      - In [Fe(CN)6]4-, Fe2+ acts as the central ion, which accepts electrons from the CN- ligands.
      - In [Cu(NH3)4]2+, Cu2+ acts as the central ion, which accepts electrons from the NH3 ligands.
      - In [Ag(NH3)2]+, Ag+ acts as the central ion, which accepts electrons from the NH3 ligands.

      Conclusion:
      Thus, we can conclude that in the formation of a complex entity, the central atom/ion acts as a Lewis acid because it accepts a pair of electrons from the ligands to form a coordinate covalent bond.

      Which is the diamagnetic?
      • a)
        [CoF6]3-
      • b)
        [Ni(CN)4]2-
      • c)
        [NiCI3]2-
      • d)
        [Fe(CN)6]3-
      Correct answer is option 'B'. Can you explain this answer?

      Niti Mishra answered
      Explanation:

      Diamagnetic substances are those which do not have any unpaired electrons and are not attracted by a magnetic field. On the other hand, paramagnetic substances have unpaired electrons and are attracted by a magnetic field.

      Let's examine the given options to determine which one is diamagnetic.

      [CoF6]3-
      Cobalt has 27 electrons. In this complex, cobalt is in the +3 oxidation state. The six fluoride ions act as ligands and each donate one pair of electrons to the cobalt ion. The complex has a total of 33 electrons, and there are three unpaired electrons in the d-orbitals of the cobalt ion. Therefore, [CoF6]3- is a paramagnetic complex.

      [Ni(CN)4]2-
      Nickel has 28 electrons. In this complex, nickel is in the +2 oxidation state. The four cyanide ions act as ligands and each donate one pair of electrons to the nickel ion. The complex has a total of 34 electrons, and all the electrons are paired. Therefore, [Ni(CN)4]2- is a diamagnetic complex.

      [NiCl4]2-
      Similar to the above complex, nickel has 28 electrons and is in the +2 oxidation state. The four chloride ions act as ligands and each donate one pair of electrons to the nickel ion. The complex has a total of 32 electrons, and all the electrons are paired. Therefore, [NiCl4]2- is a diamagnetic complex.

      [Fe(CN)6]3-
      Iron has 26 electrons. In this complex, iron is in the +3 oxidation state. The six cyanide ions act as ligands and each donate one pair of electrons to the iron ion. The complex has a total of 32 electrons, and there are five unpaired electrons in the d-orbitals of the iron ion. Therefore, [Fe(CN)6]3- is a paramagnetic complex.

      Therefore, the diamagnetic complex among the given options is [Ni(CN)4]2-.

      Can you explain the answer of this question below:

      sp3-hybridisation is found in

      • A:

        [ZnCI4]2-

      • B:

        [Cu(NH3)4]2+

      • C:

        [CuCI4]2-

      • D:

        [Ni(CO)4]

      The answer is A,C,D.

      Dipika Rane answered
      Explanation:

      SP3 hybridization is a type of hybridization where one s orbital and three p orbitals of the same shell of an atom mix to form four sp3 hybrid orbitals. These hybrid orbitals are arranged in a tetrahedral shape around the central atom.

      The given options are:

      a) [ZnCl4]2-
      b) [Cu(NH3)4]2
      c) [CuCl4]2-
      d) [Ni(CO)4]

      a) [ZnCl4]2-: In this complex ion, the central zinc atom is sp3 hybridized. The zinc ion has an electronic configuration of [Ar]3d104s0. The hybridization of the zinc ion takes place by mixing one 4s orbital and three 4p orbitals to form four sp3 hybrid orbitals.

      b) [Cu(NH3)4]2: In this complex ion, the central copper atom is dsp2 hybridized. The copper ion has an electronic configuration of [Ar]3d104s1. The hybridization of the copper ion takes place by mixing one 4s orbital, two 4p orbitals, and one 3d orbital to form five dsp2 hybrid orbitals.

      c) [CuCl4]2-: In this complex ion, the central copper atom is sp3 hybridized. The copper ion has an electronic configuration of [Ar]3d104s1. The hybridization of the copper ion takes place by mixing one 4s orbital and three 4p orbitals to form four sp3 hybrid orbitals.

      d) [Ni(CO)4]: In this complex ion, the central nickel atom is sp3 hybridized. The nickel ion has an electronic configuration of [Ar]3d84s2. The hybridization of the nickel ion takes place by mixing one 4s orbital and three 4p orbitals to form four sp3 hybrid orbitals.

      Conclusion:

      Thus, the correct options are A, C, and D, as all these complex ions have a central atom that is sp3 hybridized. The complex ion in option B has a central copper atom that is dsp2 hybridized.

      In the complex Fe(CO)x, the value of x is
      • a)
        3
      • b)
        2
      • c)
        4
      • d)
        5
      Correct answer is option 'D'. Can you explain this answer?

      Maitri Sharma answered
      Complex carbonyls follow Sidwick's EAN rule i.e compound with EAN 36 will be relatively more stable than other metal carbonyls. Iron pentacarbonyl has EAN number of 36 = Z−X+Y = (26−0+2x)
      [Z = atomic number, X = oxidation state of metal, Y= total electrons donated by ligand]
      ∴x = 5. So, the formula will be Fe(CO)5.

      For the complex ion dichlorido bis (ethylene diamine) cobalt (III), select the correct statement.
      • a)
        It has three isomers, two of them are optically active and one is optically inactive.
      • b)
        It has three isomers, all of them are optically active.
      • c)
        It has three isomers, all of them are optically inactive.
      • d)
        It has one optically active isomer and two geometrical isomers.
      Correct answer is option 'A'. Can you explain this answer?

      Milan Datta answered
      Explanation:

      The complex ion dichlorido bis(ethylene diamine) cobalt (III) has the formula [Co(en)2Cl2]+. Let's analyze the structure and isomers of this complex ion to determine the correct statement.

      Structure:
      The central cobalt (III) ion is coordinated by two ethylenediamine (en) ligands and two chloride (Cl) ligands. The ethylenediamine ligand is a bidentate ligand, meaning that it can form two coordination bonds with the central metal ion. The chloride ligand is a monodentate ligand, meaning that it can form only one coordination bond with the central metal ion.

      Isomers:
      Isomers are compounds that have the same chemical formula but different structural arrangements. In this case, there are three possible isomers for the complex ion [Co(en)2Cl2]+.

      1. Geometrical isomerism:
      Geometrical isomerism occurs when there is restricted rotation around a bond, resulting in different spatial arrangements. In the case of [Co(en)2Cl2]+, there are two possible geometrical isomers:

      - cis-[Co(en)2Cl2]+: In this isomer, the two ethylenediamine ligands are adjacent to each other, and the two chloride ligands are also adjacent to each other.
      - trans-[Co(en)2Cl2]+: In this isomer, the two ethylenediamine ligands are opposite to each other, and the two chloride ligands are also opposite to each other.

      2. Optical isomerism:
      Optical isomerism occurs when a compound is chiral, meaning it does not possess a plane of symmetry. Chiral compounds exist in two forms known as enantiomers, which are mirror images of each other. In the case of [Co(en)2Cl2]+, there is only one chiral center, which is the cobalt ion.

      - Each geometrical isomer can exist as either an R or S enantiomer, resulting in two optically active isomers.
      - The trans-[Co(en)2Cl2]+ isomer is optically inactive because its mirror image can be superimposed on it.

      Conclusion:
      Based on the analysis, the correct statement is option A. The complex ion dichlorido bis(ethylene diamine) cobalt (III) has three isomers, two of them are optically active (cis-[Co(en)2Cl2]+ R and S enantiomers) and one is optically inactive (trans-[Co(en)2Cl2]+).

      The IUPAC name of the compound K[SbCl5Ph] is
      • a)
        Potassium chlorophenylantimonate (V)
      • b)
        Potassium pentachloro(phenyl) antimonate (V)
      • c)
        Potassium pentachlorobenzylantimonate (V)
      • d)
        None of the above
      Correct answer is option 'B'. Can you explain this answer?

      Rutuja Ahuja answered
      The correct option is B Potassium pentachloro(phenyl) antimonate(V)
      IUPAC naming of coordination compound:

      The names of coordination compounds are derived by the following principles of nomenclature,
      1. The cation is named first in both positively and negatively charged coordination entities.
      2. The ligands are named in an alphabetical order before the name of the central atom/ion.
      3. When coordination entity is anionic, the name of central metal atom end with 'ate' followed by its oxidation number in roman numericals.

      In given compound, the charge on coordination entity is -1.
      Cl− and phenyl are monodentate anionic ligand.
      Thus, the oxidation state of Sb is +5.
      Hence, the IUPAC name of the compound K[SbCl5Ph] is Potassium pentachloro(phenyl)antimonate(V)

      In which of the following porphyrin acts as ligand?
      • a)
        Haemoglobin
      • b)
        Chlorophyll
      • c)
        Vitamin B-12
      • d)
        Insulin
      Correct answer is option 'A,B'. Can you explain this answer?

      Ciel Knowledge answered
      he porphyrin ring contains pyrrote unit are linked by four (—CH =)bridges. Porphyrine are derived from porphin, varying according to the nature of substituents. Porphyrin ring act as tetradentate ligands with four pyrole like nitrogens surrounding a central site of metals.. Iron complex of the substituted porphin is here. When magnesium lie at the centre of substituted porphin ring; the resulting complex is called chlorophyll.

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