Coordination Compounds · JEE Main previous year questions

2025 19 questions

1. Q522025 · 8 Apr 2025 · Shift 2

   Match the LIST-I with LIST-II | LIST-I (Complex/ Species) | LIST-II (Shape & magnetic moment) | | :--- | :--- | | A. $[{\mathrm{Ni}(\mathrm{CO})}_4]$ | I. Tetrahedral, 2.8 BM | | B. $[{\mathrm{Ni}(\mathrm{CN})}_4{]}^{2-}$ | II. Square planar, 0 BM | | C. $[{\mathrm{NiCl}}_4{]}^{2-}$ | III. Tetrahedral, 0 BM | | D. $[{\mathrm{MnBr}}_4{]}^{2-}$ | IV. Tetrahedral, 5.9 BM | Choose the correct answer from the options given below:

   1. A.A-I, B-II, C-III, D-IV
   2. B.A-IV, B-I, C-III, D-II
   3. C.A-III, B-II, C-I, D-IV
   4. D.A-III, B-IV, C-II, D-I
   Show answer

   Answer: C

2. Q602025 · 8 Apr 2025 · Shift 2

   The number of species from the following that are involved in $\mathrm{s}{\mathrm{p}}^3{\mathrm{d}}^2$ hybridization is : ${\left[\mathrm{Co}(\mathrm{N}{\mathrm{H}}_3{)}_6\right]}^{3+},\mathrm{S}{\mathrm{F}}_6,{\left[\mathrm{Cr}{\mathrm{F}}_6\right]}^{3-},{\left[\mathrm{Co}{\mathrm{F}}_6\right]}^{3-},{\left[\mathrm{Mn}(\mathrm{CN}{)}_6\right]}^{3-}$, and ${\left[\mathrm{MnC}{\mathrm{l}}_6\right]}^{3-}$

   1. A.4
   2. B.3
   3. C.5
   4. D.6
   Show answer

   Answer: B

3. Q652025 · 8 Apr 2025 · Shift 2

   Given below are two statements: Statement I: A homoleptic octahedral complex, formed using monodentate ligands, will not show stereoisomerism. Statement II: cis- and trans- platin are heteroleptic complexes of Pd. In the light of the above statements, choose the correct answer from the options given below:

   1. A.Statement I is true but Statement II is false
   2. B.Both Statement I and Statement II are true
   3. C.Both Statement I and Statement II are false
   4. D.Statement I is false but Statement II is true
   Show answer

   Answer: A

4. Q612025 · 4 Apr 2025 · Shift 1

   Which one of the following complexes will have ${\Delta }_{\mathrm{o}}=0$ and $\mu =5.96B.M.?$

   1. A.$[\mathrm{Fe}{\mathrm{F}}_6{]}^{4-}$
   2. B.$[\mathrm{Mn}(\mathrm{SCN}{)}_6{]}^{4-}$
   3. C.$[\mathrm{Co}(\mathrm{N}{\mathrm{H}}_3{)}_6{]}^{3+}$
   4. D.$[\mathrm{Fe}(\mathrm{CN}{)}_6{]}^{4-}$
   Show answer

   Answer: B

5. Q642025 · 4 Apr 2025 · Shift 1

   Number of stereoisomers possible for the complexes, $[\mathrm{CrC}{\mathrm{l}}_3(\mathrm{py}{)}_3]$ and $[\mathrm{CrC}{\mathrm{l}}_2(\mathrm{ox}{)}_2{]}^{3-}$ are respectively ($py=\text{pyridine},ox=\text{oxalate}$ )

   1. A.3 & 3
   2. B.2 & 3
   3. C.1 & 2
   4. D.2 & 2
   Show answer

   Answer: B

6. Q632025 · 4 Apr 2025 · Shift 2

   ' $X$ ' is the number of electrons in $t_{2g}$ orbitals of the most stable complex ion among $[\text{Fe}({\text{NH}}_3{)}_6{]}^{3+}$, $[{\text{FeCl}}_6{]}^{3-}$, $[\text{Fe}({\text{C}}_2{\text{O}}_4{)}_3{]}^{3-}$ and $[\text{Fe}({\text{H}}_2\text{O}{)}_6{]}^{3+}$. The nature of oxide of vanadium of the type ${\text{V}}_2{\text{O}}_X$ is :

   1. A.Amphoteric
   2. B.Acidic
   3. C.Basic
   4. D.Neutral
   Show answer

   Answer: C

7. Q672025 · 4 Apr 2025 · Shift 2

   The correct order of $[{\mathrm{FeF}}_6{]}^{3-}$, $[{\mathrm{CoF}}_6{]}^{3-}$, $[\mathrm{Ni}(\mathrm{CO}{)}_4]$ and $[\mathrm{Ni}(\mathrm{CN}{)}_4{]}^{2-}$ complex species based on the number of unpaired electrons present is:

   1. A.$[{\mathrm{CoF}}_6{]}^{3-}>[{\mathrm{FeF}}_6{]}^{3-}>[\mathrm{Ni}(\mathrm{CO}{)}_4]>[\mathrm{Ni}(\mathrm{CN}{)}_4{]}^{2-}$
   2. B.$[{\mathrm{FeF}}_6{]}^{3-}>[{\mathrm{CoF}}_6{]}^{3-}>[\mathrm{Ni}(\mathrm{CN}{)}_4{]}^{2-}>[\mathrm{Ni}(\mathrm{CO}{)}_4]$
   3. C.$[{\mathrm{FeF}}_6{]}^{3-}>[{\mathrm{CoF}}_6{]}^{3-}>[\mathrm{Ni}(\mathrm{CN}{)}_4{]}^{2-}=[\mathrm{Ni}(\mathrm{CO}{)}_4]$
   4. D.$[\mathrm{Ni}(\mathrm{CN}{)}_4{]}^{2-}>[{\mathrm{FeF}}_6{]}^{3-}>[{\mathrm{CoF}}_6{]}^{3-}>[\mathrm{Ni}(\mathrm{CO}{)}_4]$
   Show answer

   Answer: C

8. Q512025 · 3 Apr 2025 · Shift 1

   The correct order of the complexes $[\mathrm{Co}(\mathrm{N}{\mathrm{H}}_3{)}_5({\mathrm{H}}_2\mathrm{O}){]}^{3+}$ (A), $[\mathrm{Co}(\mathrm{N}{\mathrm{H}}_3{)}_6{]}^{3+}$ (B), $[\mathrm{Co}(\mathrm{CN}{)}_6{]}^{3-}$ (C) and $[\mathrm{CoCl}(\mathrm{N}{\mathrm{H}}_3{)}_5{]}^{2+}$ (D) in terms of wavelength of light absorbed is

   1. A.$\mathrm{D}>\mathrm{C}>\mathrm{B}>\mathrm{A}$
   2. B.$\mathrm{C}>\mathrm{B}>\mathrm{A}>\mathrm{D}$
   3. C.$\mathrm{D}>\mathrm{A}>\mathrm{B}>\mathrm{C}$
   4. D.$\mathrm{C}>\mathrm{B}>\mathrm{D}>\mathrm{A}$
   Show answer

   Answer: C

9. Q592025 · 3 Apr 2025 · Shift 2

   Identify the diamagnetic octahedral complex ions from below ; A. $[\mathrm{Mn}(\mathrm{CN}{)}_6{]}^{3-}$ B. $[\mathrm{Co}({\mathrm{NH}}_3{)}_6{]}^{3+}$ C. $[\mathrm{Fe}(\mathrm{CN}{)}_6{]}^{4-}$ D. $[\mathrm{Co}({\mathrm{H}}_2\mathrm{O}{)}_3{\mathrm{F}}_3]$ Choose the correct answer from the options given below:

   1. A.B and C Only
   2. B.A and C Only
   3. C.B and D Only
   4. D.A and D Only
   Show answer

   Answer: A

10. Q562025 · 2 Apr 2025 · Shift 1

    Choose the correct tests with respective observations. (A) ${\mathrm{CuSO}}_4$ (acidified with acetic acid) $+{\mathrm{K}}_4[\mathrm{Fe}(\mathrm{CN}{)}_6]\to$ Chocolate brown precipitate. (B) ${\mathrm{FeCl}}_3+{\mathrm{K}}_4[\mathrm{Fe}(\mathrm{CN}{)}_6]\to$ Prussian blue precipitate. (C) ${\mathrm{ZnCl}}_2+{\mathrm{K}}_4[\mathrm{Fe}(\mathrm{CN}{)}_6]$, neutralised with ${\mathrm{NH}}_4\mathrm{OH}\to$ White or bluish white precipitate. (D) ${\mathrm{MgCl}}_2+{\mathrm{K}}_4[\mathrm{Fe}(\mathrm{CN}{)}_6]\to$ Blue precipitate. (E) ${\mathrm{BaCl}}_2+{\mathrm{K}}_4[\mathrm{Fe}(\mathrm{CN}{)}_6]$, neutralised with $\mathrm{NaOH}\to$ White precipitate. Choose the correct answer from the options given below :

    1. A.A, D and E only
    2. B.A, B and C only
    3. C.B, D and E only
    4. D.C, D and E only
    Show answer

    Answer: B

11. Q592025 · 2 Apr 2025 · Shift 1

    Given below are two statements : Statement (I) : In octahedral complexes, when ${\Delta }_0<\mathrm{P}$ high spin complexes are formed. When ${\Delta }_0>P$ low spin complexes are formed. Statement (II) : In tetrahedral complexes because of ${\Delta }_t<P$, low spin complexes are rarely formed. In the light of the above statements, choose the most appropriate answer from the options given below :

    1. A.Both Statement I and Statement II are incorrect
    2. B.Statement I is correct but Statement II is incorrect
    3. C.Statement I is incorrect but Statement II is correct
    4. D.Both Statement I and Statement II are correct
    Show answer

    Answer: D

12. Q632025 · 2 Apr 2025 · Shift 2

    Formation of $\mathrm{N}{\mathrm{a}}_4[\mathrm{Fe}(\mathrm{CN}{)}_5\mathrm{NOS}]$, a purple coloured complex formed by addition of sodium nitroprusside in sodium carbonate extract of salt indicates the presence of :

    1. A.Sulphide ion
    2. B.Sulphite ion
    3. C.Sulphate ion
    4. D.Sodium ion
    Show answer

    Answer: A

13. Q732025 · 2 Apr 2025 · Shift 2· Numerical answer

    The spin-only magnetic moment value of ${\mathrm{M}}^{\mathrm{n}+}$ ion formed among $\mathrm{Ni}$, $\mathrm{Zn}$, $\mathrm{Mn}$ and $\mathrm{Cu}$ that has the least enthalpy of atomisation is ____ . (in nearest integer) Here n is equal to the number of diamagnetic complexes among ${\mathrm{K}}_2[\mathrm{NiC}{\mathrm{l}}_4]$, $[\mathrm{Zn}({\mathrm{H}}_2\mathrm{O}{)}_6]\mathrm{C}{\mathrm{l}}_2$, ${\mathrm{K}}_3[\mathrm{Mn}(\mathrm{CN}{)}_6]$ and $[\mathrm{Cu}(\mathrm{PP}{\mathrm{h}}_3{)}_3\mathrm{I}]$

    Show answer

    Answer: 0

14. Q582025 · 29 Jan 2025 · Shift 2

    Identify the homoleptic complexes with odd number of $d$ electrons in the central metal : (A) $[\mathrm{Fe}{\mathrm{O}}_4{]}^{2-}$ (B) $[\mathrm{Fe}(\mathrm{CN}{)}_6{]}^{3-}$ (C) $[\mathrm{Fe}(\mathrm{CN}{)}_5\mathrm{NO}{]}^{2-}$ (D) $[\mathrm{CoC}{\mathrm{l}}_4{]}^{2-}$ (E) $[\mathrm{Co}({\mathrm{H}}_2\mathrm{O}{)}_3{\mathrm{F}}_3]$ Choose the correct answer from the options given below :

    1. A.(C) and (E) only
    2. B.(A), (B) and (D) only
    3. C.(B) and (D) only
    4. D.(A), (C) and (E) only
    Show answer

    Answer: C

15. Q722025 · 29 Jan 2025 · Shift 2· Numerical answer

    Consider the following low-spin complexes $${\mathrm{K}}_3[\mathrm{Co}(\mathrm{N}{\mathrm{O}}_2{)}_6],{\mathrm{K}}_4[\mathrm{Fe}(\mathrm{CN}{)}_6],{\mathrm{K}}_3[\mathrm{Fe}(\mathrm{CN}{)}_6],\mathrm{C}{\mathrm{u}}_2[\mathrm{Fe}(\mathrm{CN}{)}_6]\text{ and }\mathrm{Z}{\mathrm{n}}_2[\mathrm{Fe}(\mathrm{CN}{)}_6]$$ The sum of the spin-only magnetic moment values of complexes having yellow colour is ____ B.M. (answer in nearest integer)

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    Answer: 0

16. Q632025 · 28 Jan 2025 · Shift 1

    The metal ion whose electronic configuration is not affected by the nature of the ligand and which gives a violet colour in non-luminous flame under hot condition in borax bead test is

    1. A.$\mathrm{C}{\mathrm{r}}^{3+}$
    2. B.$\mathrm{T}{\mathrm{i}}^{3+}$
    3. C.$\mathrm{N}{\mathrm{i}}^{2+}$
    4. D.$\mathrm{M}{\mathrm{n}}^{2+}$
    Show answer

    Answer: C

17. Q632025 · 24 Jan 2025 · Shift 2

    The conditions and consequence that favours the ${t_{2\mathrm{g}}}^3{e_{\mathrm{g}}}^1$ configuration in a metal complex are :

    1. A.strong field ligand, low spin complex
    2. B.strong field ligand, high spin complex
    3. C.weak field ligand, high spin complex
    4. D.weak field ligand, low spin complex
    Show answer

    Answer: C

18. Q622025 · 23 Jan 2025 · Shift 2
    
    1. A.(B), (C) and (D) only
    2. B.(C) and (E) only
    3. C.$(A)$, $(B)$ and $(E)$ only
    4. D.(B) and (D) only
    Show answer

    Answer: D

19. Q662025 · 22 Jan 2025 · Shift 1

    In which of the following complexes the CFSE, ${\Delta }_o$ will be equal to zero?

    1. A.${\mathrm{K}}_3\left[\mathrm{Fe}(\mathrm{SCN}{)}_6\right]$
    2. B.$\left[\mathrm{Fe}(\mathrm{en}{)}_3\right]{\mathrm{Cl}}_3$
    3. C.$\left[\mathrm{Fe}({\mathrm{NH}}_3{)}_6\right]{\mathrm{Br}}_2$
    4. D.${\mathrm{K}}_4\left[\mathrm{Fe}(\mathrm{CN}{)}_6\right]$
    Show answer

    Answer: A