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Coordination Compounds

JEE Main 2025 (Online) 22nd January Morning ShiftMCQMedium📈 Topic in 32% papers+4−1
Ques. 1JEE Main 2025, 22 January (Morning Shift)

From the magnetic behaviour of [NiCl4]2- (paramagnetic) and [Ni(CO)4] (diamagnetic), choose the correct geometry and oxidation state.

  1. [NiCl4]2- : Ni(0), tetrahedral [Ni(CO)4] : Ni(0), square planar
  2. [NiCl4]2- : NiII, tetrahedral [Ni(CO)4] : Ni(0), tetrahedral
  3. [NiCl4]2- : NiII, tetrahedral [Ni(CO)4] : NiII, square planar
  4. [NiCl4]2- : NiII, square planar [Ni(CO)4] : Ni(0), square planar

Answer

(2) [NiCl4]2- : NiII, tetrahedral [Ni(CO)4] : Ni(0), tetrahedral

Solution

In [NiCl4]2- nickel is Ni2+ (3d8), and since Cl- is a weak-field ligand there is no pairing:

[figure]

Hence it is sp3, tetrahedral, with 2 unpaired electrons (paramagnetic).

In [Ni(CO)4] nickel is Ni(0), 3d10, because strong-field CO pairs the 4s electrons into 3d:

[figure]

Hence it is sp3, tetrahedral and diamagnetic.

Answer: (2)

Keep practising — Coordination Compounds

Ques. 2JEE Main 2025, 22 January (Morning Shift)

In which of the following complexes the CFSE, o will be equal to zero?

  1. K3[Fe(SCN)6]
  2. [Fe(en)3]Cl3
  3. [Fe(NH3)6]Br2
  4. K4[Fe(CN)6]
Ques. 3JEE Main 2025, 22 January (Evening Shift)

The correct order of the following complexes in terms of their crystal field stabilization energies is :

  1. [Co(NH3)4]2+ < [Co(NH3)6]2+ < [Co(NH3)6]3+ < [Co(en)3]3+
  2. [Co(NH3)4]2+ < [Co(NH3)6]2+ < [Co(en)3]3+ < [Co(NH3)6]3+
  3. [Co(NH3)6]2+ < [Co(NH3)6]3+ < [Co(NH3)4]2+ < [Co(en)3]3+
  4. [Co(en)3]3+ < [Co(NH3)6]3+ < [Co(NH3)6]2+ < [Co(NH3)4]2+
Ques. 4JEE Main 2025, 22 January (Evening Shift)

Identify the homoleptic complex(es) that is/are low spin. Choose the correct answer from the options given below :

  1. C and D only
  2. C only
  3. A and C only
  4. B and E only
Ques. 5JEE Main 2025, 22 January (Evening Shift)

The complex of Ni2+ ion and dimethyl glyoxime contains number of Hydrogen (H) atoms.

Ques. 6JEE Main 2024, 9 April (Morning Shift)

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). In the light of the above statements, choose the most appropriate answer from the options given below :

  1. (A) is correct but (R) is not correct
  2. (A) is not correct but (R) is correct
  3. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
  4. Both (A) and (R) are correct and (R) is the correct explanation of (A)
Ques. 7JEE Main 2024, 9 April (Morning Shift)

Number of ambidentate ligands among the following is . NO2-, SCN-, C2O42-, NH3, CN-, SO42-, H2O.

Ques. 8JEE Main 2024, 9 April (Evening Shift)

Match List I with List II Choose the correct answer from the options given below:

  1. A-III, B-II, C-IV, D-I
  2. A-III, B-I, C-II, D-IV
  3. A-I, B-III, C-II, D-IV
  4. A-III, B-I, C-IV, D-II
Ques. 9JEE Main 2024, 9 April (Evening Shift)

The coordination environment of Ca2+ ion in its complex with EDTA4- is :

  1. trigonal prismatic
  2. octahedral
  3. square planar
  4. tetrahedral
Ques. 10JEE Main 2024, 8 April (Morning Shift)

Number of Complexes with even number of electrons in t2g orbitals is - [Fe(H2O)6]2+, [Co(H2O)6]2+, [Co(H2O)6]3+, [Cu(H2O)6]2+, [Cr(H2O)6]2+

  1. 3
  2. 2
  3. 1
  4. 5
Ques. 11JEE Main 2024, 8 April (Morning Shift)

An octahedral complex with the formula CoCl3 nNH3 upon reaction with excess of AgNO3 solution gives 2 moles of AgCl. Consider the oxidation state of Co in the complex is 'x'. The value of "x + n" is .

  1. 6
  2. 5
  3. 3
  4. 8

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