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Coordination Compounds

JEE Main 2026 (Online) 28th January Morning ShiftMCQEasy📈 Topic in 33% papers+4−1
Ques. 1JEE Main 2026, 28 January (Morning Shift)

The correct statement among the following is:

  1. [Ni(CN)4]2- and [NiCl4]2- are diamagnetic and Ni(CO)4 is paramagnetic.
  2. Ni(CO)4 is diamagnetic and [NiCl4]2- and [Ni(CN)4]2- are paramagnetic.
  3. Ni(CO)4 and [NiCl4]2- are diamagnetic and [Ni(CN)4]2- is paramagnetic.
  4. Ni(CO)4 and [Ni(CN)4]2- are diamagnetic and [NiCl4]2- is paramagnetic.

Answer

(4) Ni(CO)4 and [Ni(CN)4]2- are diamagnetic and [NiCl4]2- is paramagnetic.

Solution

Ni(CO)4: Ni(0), 3d8 4s2; strong field CO pairs all electrons into 3d ( 3d10), sp3, tetrahedral no unpaired electron, diamagnetic.

[Ni(CN)4]2-: Ni2+, 3d8; strong field CN- pairs the electrons, dsp2, square planar diamagnetic.

[NiCl4]2-: Ni2+, 3d8; weak field Cl- cannot pair the electrons, sp3, tetrahedral 2 unpaired electrons, paramagnetic.

Ni(CO)4 and [Ni(CN)4]2- are diamagnetic and [NiCl4]2- is paramagnetic.

Answer: (4)

Keep practising — Coordination Compounds

Ques. 2JEE Main 2026, 28 January (Morning Shift)

X is the number of geometrical isomers exhibited by [Pt(NH3)(H2O)BrCl]. Y is the number of optically inactive isomer(s) exhibited by [CrCl2(ox)2]3-. Z is the number of geometrical isomers exhibited by [Co(NH3)3(NO2)3]. The value of X + Y + Z is .

Ques. 3JEE Main 2026, 28 January (Evening Shift)

The correct increasing order of spin-only magnetic moment values of the complex ions [MnBr4]2- (A), [Cu(H2O)6]2+ (B), [Ni(CN)4]2- (C) and [Ni(H2O)6]2+ (D) is :

  1. A = B < D < C
  2. C = D < B < A
  3. C < B < D < A
  4. A = B < C < D
Ques. 4JEE Main 2026, 28 January (Evening Shift)

The number of isoelectronic species among Sc3+, Cr2+, Mn3+, Co3+ and Fe3+ is ‘n’. If ‘n’ moles of AgCl is formed during the reaction of complex with formula CoCl3(en)2NH3 with excess of AgNO3 solution, then the number of electrons present in the t2g orbital of the complex is .

Ques. 5JEE Main 2026, 24 January (Morning Shift)

Given below are two statements : In the light of the above statements, choose the correct answer from the options given below

  1. Both Statement I and Statement II are false
  2. Statement I is true but Statement II is false
  3. Both Statement I and Statement II are true
  4. Statement I is false but Statement II is true
Ques. 6JEE Main 2026, 24 January (Morning Shift)

Given below are two statements: In the light of the above statements, choose the correct answer from the options given below

  1. Statement I is true but Statement II is false
  2. Both Statement I and Statement II are false
  3. Statement I is false but Statement II is true
  4. Both Statement I and Statement II are true
Ques. 7JEE Main 2026, 24 January (Morning Shift)

Consider a mixture 'X' which is made by dissolving 0.4 mol of [Co(NH3)5SO4]Br and 0.4 mol of [Co(NH3)5Br]SO4 in water to make 4 L of solution. When 2 L of mixture 'X' is allowed to react with excess of AgNO3, it forms precipitate 'Y'. The rest 2 L of mixture 'X' reacts with excess BaCl2 to form precipitate 'Z'. Which of the following statements is CORRECT?

  1. 0.1 mol of 'Y' is formed.
  2. 0.4 mol of 'Z' is formed.
  3. 0.2 mol of 'Z' is formed.
  4. 'Y' is BaSO4 and 'Z' is AgBr.
Ques. 8JEE Main 2026, 24 January (Evening Shift)

The wavelengths of light absorbed for the following complexes are in the order (I) [Co(NH3)6]3+ ; (II) [Co(H2O)6]3+ ; (III) [Co(CN)6]3- ; (IV) [Co(NH3)5(H2O)]3+ ; (V) [CoF6]3-

  1. III < IV < I < II < V
  2. III < I < IV < V < II
  3. III < I < IV < II < V
  4. III < I < II < IV < V
Ques. 9JEE Main 2026, 24 January (Evening Shift)

A chromium complex with a formula CrCl3 6H2O has a spin only magnetic moment value of 3.87 BM and its solution conductivity corresponds to 1 : 2 electrolyte. 2.75 g of the complex solution was initially passed through a cation exchanger. The solution obtained after the process was reacted with excess of AgNO3. The amount of AgCl formed in the above process is g. (Nearest integer) [Given: Molar mass in g mol-1 Cr : 52, Cl : 35.5, Ag : 108, O : 16, H : 1]

Ques. 10JEE Main 2026, 23 January (Morning Shift)

The statements that are incorrect about the nickel(II) complex of dimethylglyoxime are : Choose the correct answer from the options given below :

  1. C and E Only
  2. A, D and B Only
  3. B, C and E Only
  4. C and D Only
Ques. 11JEE Main 2026, 23 January (Morning Shift)

Given below are two statements : In the light of the above statements, choose the correct answer from the options given below :

  1. Both Statement I and Statement II are false
  2. Both Statement I and Statement II are true
  3. Statement I is false but Statement II is true
  4. Statement I is true but Statement II is false

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