jee main chemistry important questions | Coordination Compounds jee main questions FREE

Q 1 :
Number of complexes from the following with even number of unpaired $'' d''$ electrons is __________ .

${[{V(H}_{2} {O)}_{6}]}^{3 +}, {[{Cr(H}_{2} {O)}_{6}]}^{2 +}, {[{Fe(H}_{2} {O)}_{6}]}^{3 +}, {[{Ni(H}_{2} {O)}_{6}]}^{3 +}, {[{Cu(H}_{2} {O)}_{6}]}^{2 +}$

[Given atomic numbers: V = 23, Cr = 24, Fe = 26, Ni = 28, Cu = 29] [2024]

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(A)

Complex	Electronic configuration of central metal ion without crystal field splitting	Electronic configuration of central metal ion after crystal field splitting	Number of unpaired d electrons in complex
${[{V(H}_{2} {O)}_{6}]}^{3 +}$	$V^{3 +} = {}_{18}{[Ar]} 3 d^{2}$	$t_{2 g}^{1, 1, 0}, e_{g}^{0, 0}$	2
${[{Cr(H}_{2} {O)}_{6}]}^{2 +}$	${Cr}^{2 +} = {}_{18}{[Ar]} 3 d^{4}$	$t_{2 g}^{1, 1, 1}, e_{g}^{1, 0}$	4
${[{Fe(H}_{2} {O)}_{6}]}^{3 +}$	${Fe}^{3 +} = {}_{18}{[Ar]} 3 d^{5}$	$t_{2 g}^{1, 1, 1}, e_{g}^{1, 1}$	5
${[{Ni(H}_{2} {O)}_{6}]}^{3 +}$	${Ni}^{3 +} = {}_{18}{[Ar]} 3 d^{7}$	$t_{2 g}^{2, 2, 1}, e_{g}^{1, 1}$	3
${[{Cu(H}_{2} {O)}_{6}]}^{2 +}$	${Cu}^{2 +} = {}_{18}{[Ar]} 3 d^{9}$	$t_{2 g}^{2, 2, 2}, e_{g}^{2, 1}$	1

Q 2 :
The correct sequence of ligands in the order of decreasing field strength is : [2024]

$S^{2 -} > {}^{-}{OH} > {EDTA}^{4 -} > CO$
${}^{-}{OH} > F^{-} > {NH}_{3} > {CN}^{-}$
$CO > H_{2} O > F^{-} > S^{2 -}$
${NCS}^{-} > {EDTA}^{4 -} > {CN}^{-} > CO$

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(C)

Ligands can be arranged in a series in the order of increasing field strength as given below:

$I^{-} < {Br}^{-} < {SCN}^{-} < {Cl}^{-} < S^{2 -} < F^{-} < {OH}^{-} < C_{2} O_{4}^{2 -} < H_{2} O < {NCS}^{-} < {edta}^{4 -} < {NH}_{3} < en < {CN}^{-} < CO$

Q 3 :
If an iron (III) complex with the formula ${[Fe {({NH}_{3})}_{x} {(CN)}_{y}]}^{-}$ has no electron in its $e_{g}$ orbital, then the value of x + y is [2024]

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(D)

Iron in +3 oxidation state forms complexes with C.N. = 6.

So $x + y = 6 .$

${[{Fe(NH}_{3})_{x} {(CN)}_{y}]}^{-}$

Ammonia is a neutral ligand and cyanide is a unit negatively charged ligand.

Since sum of oxidation number = charge

$O.N of Fe + x \times 0 + y \times (- 1) = - 1$

$3 + (- y) = - 1$

$y = 4$

Thus $x = 2$

The complex is ${[{Fe(NH}_{3})_{2} {(CN)}_{4}]}^{-}$

Q 4 :
The number of unpaired $d$ -electrons in ${[{Co(H}_{2} {O)}_{6}]}^{3 +}$ is ________ . [2024]

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(B)

${[{Co(H}_{2} {O)}_{6}]}^{3 +}$

Oxidation number of Co = +3

${Co}^{3 +} = {}_{18}{[Ar]} 3 d^{6}$

With ${Co}^{3 +}$ , ligands like $H_{2} O$ acts as strong field ligands. With strong field ligands, $d^{6}$ complexes split as $t_{2 g}^{2, 2, 2}, e_{g}^{0, 0}$

So it has no unpaired electrons.

Q 5 :
The correct order of ligands arranged in increasing field strength. [2024]

$H_{2} O < {}^{-}{OH} < {CN}^{-} < {NH}_{3}$
${Cl}^{-} < {}^{-}{OH} < {Br}^{-} < {CN}^{-}$
${Br}^{-} < F^{-} < H_{2} O < {NH}_{3}$
$F^{-} < {Br}^{-} < I^{-} < {NH}_{3}$

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(C)

In general, ligands can be arranged in a series in the order of increasing field strength as given below:

$I^{-} < {Br}^{-} < {SCN}^{-} < {Cl}^{-} < S^{2 -} < F^{-} < {OH}^{-} < C_{2} O_{4}^{2 -} < H_{2} O < {NCS}^{-} < {edta}^{4 -} < {NH}_{3} < en < {CN}^{-} < CO$

Q 6 :
Which one of the following complexes will exhibit the least paramagnetic behaviour ?

[Atomic number, Cr = 24, Mn = 25, Fe = 26, Co = 27] [2024]

${[Co {(H_{2} O)}_{6}]}^{2 +}$
${[Mn {(H_{2} O)}_{6}]}^{2 +}$
${[Fe {(H_{2} O)}_{6}]}^{2 +}$
${[Cr {(H_{2} O)}_{6}]}^{2 +}$

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(A)

Complex	Electronic configuration of central metal ion without splitting	Electronic configuration after splitting	Number of unpaired electrons
${[{Co(H}_{2} {O)}_{6}]}^{2 +}$	${Co}^{2 +} = {}_{18}{[Ar]} 3 d^{7}$	$t_{2 g}^{2, 2, 1} e_{g}^{1, 1}$	3
${[{Mn(H}_{2} {O)}_{6}]}^{2 +}$	${Mn}^{2 +} = {}_{18}{[Ar]} 3 d^{5}$	$t_{2 g}^{1, 1, 1} e_{g}^{1, 1}$	5
${[{Fe(H}_{2} {O)}_{6}]}^{2 +}$	${Fe}^{2 +} = {}_{18}{[Ar]} 3 d^{6}$	$t_{2 g}^{2, 1, 1} e_{g}^{1, 1}$	4
${[{Cr(H}_{2} {O)}_{6}]}^{2 +}$	${Cr}^{2 +} = {}_{18}{[Ar]} 3 d^{4}$	$t_{2 g}^{1, 1, 1} e_{g}^{1, 0}$	4

Paramagnetic nature $\propto$ number of unpaired electrons.

Q 7 :
The number of complexes from the following with no electrons in the $t_{2}$ orbital is _______ .

${TiCl}_{4}, {[{MnO}_{4}]}^{-}, {[{FeO}_{4}]}^{2 -}, {[{FeCl}_{4}]}^{-}, {[{CoCl}_{4}]}^{2 -}$ [2024]

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(D)

Compound	Electronic configuration of central atom without tetrahedral splitting	Electronic configuration of central atom after tetrahedral splitting
${TiCl}_{4}$	${Ti}^{ü +} = {}_{18}{[Ar]} 3 d 4 s$	$e^{0} t_{2}^{0}$
${MnO}_{4}^{-}$	${Mn}^{7 +} = {}_{18}{[Ar]} 3 d^{0} 4 s^{0}$	$e^{0} t_{2}^{0}$
${FeO}_{4}^{2 -}$	${Fe}^{6 +} = {}_{18}{[Ar]} 3 d^{2} 4 s^{0}$	$e^{2} t_{2}^{0}$
${FeCl}_{4}^{-}$	${Fe}^{2 +} = {}_{18}{[Ar]} 3 d^{6} 4 s^{0}$	$e^{3} t_{2}^{3}$
${CoCl}_{4}^{2 -}$	${Co}^{2 +} = {}_{18}{[Ar]} 3 d^{7} 4 s^{0}$	$e^{4} t_{2}^{3}$

Three complexes donot have electron in $t_{2}$ orbitals

Q 8 :
Match List I with List II.

List I List II

Tetrahedral Complex Electronic Configuration

A. ${TiCl}_{4}$ I. $e^{2}, t_{2}^{0}$

B. ${[{FeO}_{4}]}^{2 -}$ II. $e^{4}, t_{2}^{3}$

C. ${[{FeCl}_{4}]}^{-}$ III. $e^{0}, t_{2}^{0}$

D. ${[{CoCl}_{4}]}^{2 -}$ IV. $e^{2}, t_{2}^{3}$

Choose the correct answer from the options given below: [2024]

(A) - (III), (B) - (I), (C) - (IV), (D) - (II)
(A) - (III), (B) - (IV), (C) - (II), (D) - (I)
(A) - (IV), (B) - (III), (C) - (I), (D) - (II)
(A) - (I), (B) - (III), (C) - (IV), (D) - (II)

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(A)

Complex	Electronic configuration of central metal without tetrahedral splitting	Electronic configuration of central metal with tetrahedral splitting
${TiCl}_{4}$	${Ti}^{4 +} = {}_{18}{[Ar]} 3 d^{0} 4 s^{0}$	$e^{0, 0}, t_{2}^{0, 0, 0}$
${[{FeO}_{4}]}^{2 -}$	${Fe}^{6 +} = {}_{18}{[Ar]} 3 d^{2} 4 s^{0}$	$e^{1, 1}, t_{2}^{0, 0, 0}$
$[{FeCl}_{4}^{-}]$	${Fe}^{3 +} = {}_{18}{[Ar]} 3 d^{5} 4 s^{0}$	$e^{1, 1}, t_{2}^{1, 1, 1}$
${[{CoCl}_{4}]}^{2 -}$	${Co}^{2 +} = {}_{18}{[Ar]} 3 d^{7} 4 s^{0}$	$e^{2, 2}, t_{2}^{1, 1, 1}$

Q 9 :
Number of complexes with even number of electrons in $t_{2 g}$ orbitals is - ${[Fe(H_{2} O)_{6}]}^{2 +}, {[Co(H_{2} O)_{6}]}^{2 +}, {[Co(H_{2} O)_{6}]}^{3 +}, {[Cu(H_{2} O)_{6}]}^{2 +}, {[Cr(H_{2} O)_{6}]}^{2 +}$ [2024]

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(A)

Complex	Electronic configuration of central metal ion without octahedral splitting	Electronic configuration of central metal ion after octahedral splitting	Number of electrons in $t_{2 g}$
${[{Fe(H}_{2} {O)}_{6}]}^{2 +}$	${Fe}^{2 +} = {}_{18}{[Ar]} 3 d^{6}$	$t_{2 g}^{2, 1, 1} e_{g}^{1, 1}$	4
${[{Co(H}_{2} {O)}_{6}]}^{2 +}$	${Co}^{2 +} = {}_{18}{[Ar]} 3 d^{7}$	$t_{2 g}^{2, 2, 1} e_{g}^{1, 1}$	5
${[{Co(H}_{2} {O)}_{6}]}^{3 +}$	${Co}^{3 +} = {}_{18}{[Ar]} 3 d^{6}$	$t_{2 g}^{2, 2, 2} e_{g}^{0, 0}$	6
${[{Cu(H}_{2} {O)}_{6}]}^{2 +}$	${Cu}^{2 +} = {}_{18}{[Ar]} 3 d^{9}$	$t_{2 g}^{2, 2, 2} e_{g}^{2, 1}$	6
${[{Cr(H}_{2} {O)}_{6}]}^{2 +}$	${Cr}^{2 +} = {}_{18}{[Ar]} 3 d^{4}$	$t_{2 g}^{1, 1, 1} e_{g}^{1, 0}$	3

Note: In complexes with C.N = 6, ${Co}^{3 +}$ undergoes $d^{2} {sp}^{3}$ hybridization (except in complexes with C.N = 6, where ${Co}^{3 +}$ undergoes ${sp}^{3} d^{2}$ hybridization).

Q 10 :
The Spin only magnetic moment value of square planar complex ${[Pt(NH}_{3})_{2} {Cl(NH}_{2} {CH}_{3})]Cl$ is ________ B.M. (Nearest integer) (Given atomic number for Pt = 78) [2024]

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(0)

In ${[Pt(NH}_{3})_{2} {Cl(NH}_{2} {CH}_{3})]Cl$ , $Pt$ is in +2 oxidation state.

${Pt}^{2 +} = {}_{54}{[Xe]} 4 f^{14} 5 d^{8}$

Metal ions with $4 d^{8}$ or $5 d^{8}$ configuration with coordination number 4 are always $d s p^{2}$ hybridized and diamagnetic, irrespective of ligand. This is because $Z_{eff}$ for these $4 d^{8}$ or $5 d^{8}$ is high on account of poor shielding of $d$ and/or $f$ electrons, hence all ligands are sufficiently attracted towards the metal ion resulting large crystal field splitting which causes in pairing up of $d^{8}$ electrons.

Topic Question Set

Q 2 :
The correct sequence of ligands in the order of decreasing field strength is : [2024]

Q 3 :
If an iron (III) complex with the formula ${[Fe {({NH}_{3})}_{x} {(CN)}_{y}]}^{-}$ has no electron in its $e_{g}$ orbital, then the value of x + y is [2024]

Q 4 :
The number of unpaired $d$ -electrons in ${[{Co(H}_{2} {O)}_{6}]}^{3 +}$ is ________ . [2024]

Q 5 :
The correct order of ligands arranged in increasing field strength. [2024]

Q 6 :
Which one of the following complexes will exhibit the least paramagnetic behaviour ?

[Atomic number, Cr = 24, Mn = 25, Fe = 26, Co = 27] [2024]

Q 7 :
The number of complexes from the following with no electrons in the $t_{2}$ orbital is _______ .

${TiCl}_{4}, {[{MnO}_{4}]}^{-}, {[{FeO}_{4}]}^{2 -}, {[{FeCl}_{4}]}^{-}, {[{CoCl}_{4}]}^{2 -}$ [2024]

Q 9 :
Number of complexes with even number of electrons in $t_{2 g}$ orbitals is - ${[Fe(H_{2} O)_{6}]}^{2 +}, {[Co(H_{2} O)_{6}]}^{2 +}, {[Co(H_{2} O)_{6}]}^{3 +}, {[Cu(H_{2} O)_{6}]}^{2 +}, {[Cr(H_{2} O)_{6}]}^{2 +}$ [2024]

Q 10 :
The Spin only magnetic moment value of square planar complex ${[Pt(NH}_{3})_{2} {Cl(NH}_{2} {CH}_{3})]Cl$ is ________ B.M. (Nearest integer) (Given atomic number for Pt = 78) [2024]

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	List I		List II
	Tetrahedral Complex		Electronic Configuration
A.	${TiCl}_{4}$	I.	$e^{2}, t_{2}^{0}$
B.	${[{FeO}_{4}]}^{2 -}$	II.	$e^{4}, t_{2}^{3}$
C.	${[{FeCl}_{4}]}^{-}$	III.	$e^{0}, t_{2}^{0}$
D.	${[{CoCl}_{4}]}^{2 -}$	IV.	$e^{2}, t_{2}^{3}$

Topic Question Set

Q 1 : Number of complexes from the following with even number of unpaired ''d'' electrons is __________ . [V(H2O)6]3+,[Cr(H2O)6]2+,[Fe(H2O)6]3+,[Ni(H2O)6]3+,[Cu(H2O)6]2+ [Given atomic numbers: V = 23, Cr = 24, Fe = 26, Ni = 28, Cu = 29] [2024]

Q 2 : The correct sequence of ligands in the order of decreasing field strength is : [2024]

Q 3 : If an iron (III) complex with the formula [Fe(NH3)x(CN)y]- has no electron in its eg orbital, then the value of x + y is [2024]

Q 4 : The number of unpaired d-electrons in [Co(H2O)6]3+ is ________ . [2024]

Q 5 : The correct order of ligands arranged in increasing field strength. [2024]

Q 6 : Which one of the following complexes will exhibit the least paramagnetic behaviour ? [Atomic number, Cr = 24, Mn = 25, Fe = 26, Co = 27] [2024]

Q 7 : The number of complexes from the following with no electrons in the t2 orbital is _______ . TiCl4,[MnO4]-,[FeO4]2-,[FeCl4]-,[CoCl4]2- [2024]

Q 8 : Match List I with List II. List I List II Tetrahedral Complex Electronic Configuration A. TiCl4 I. e2,t20 B. [FeO4]2- II. e4,t23 C. [FeCl4]- III. e0,t20 D. [CoCl4]2- IV. e2,t23 Choose the correct answer from the options given below: [2024]

Q 9 : 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+ [2024]

Q 10 : The Spin only magnetic moment value of square planar complex [Pt(NH3)2Cl(NH2CH3)]Cl is ________ B.M. (Nearest integer) (Given atomic number for Pt = 78) [2024]

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Q 2 :
The correct sequence of ligands in the order of decreasing field strength is : [2024]

Q 3 :
If an iron (III) complex with the formula ${[Fe {({NH}_{3})}_{x} {(CN)}_{y}]}^{-}$ has no electron in its $e_{g}$ orbital, then the value of x + y is [2024]

Q 4 :
The number of unpaired $d$ -electrons in ${[{Co(H}_{2} {O)}_{6}]}^{3 +}$ is ________ . [2024]

Q 5 :
The correct order of ligands arranged in increasing field strength. [2024]

Q 6 :
Which one of the following complexes will exhibit the least paramagnetic behaviour ?

[Atomic number, Cr = 24, Mn = 25, Fe = 26, Co = 27] [2024]

Q 7 :
The number of complexes from the following with no electrons in the $t_{2}$ orbital is _______ .

${TiCl}_{4}, {[{MnO}_{4}]}^{-}, {[{FeO}_{4}]}^{2 -}, {[{FeCl}_{4}]}^{-}, {[{CoCl}_{4}]}^{2 -}$ [2024]

Q 9 :
Number of complexes with even number of electrons in $t_{2 g}$ orbitals is - ${[Fe(H_{2} O)_{6}]}^{2 +}, {[Co(H_{2} O)_{6}]}^{2 +}, {[Co(H_{2} O)_{6}]}^{3 +}, {[Cu(H_{2} O)_{6}]}^{2 +}, {[Cr(H_{2} O)_{6}]}^{2 +}$ [2024]

Q 10 :
The Spin only magnetic moment value of square planar complex ${[Pt(NH}_{3})_{2} {Cl(NH}_{2} {CH}_{3})]Cl$ is ________ B.M. (Nearest integer) (Given atomic number for Pt = 78) [2024]