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]

2
4
1
5

1

2

3

4

(1)

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]

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

1

2

3

4

(3)

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]

4
3
5
6

1

2

3

4

(4)

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]

1
0
4
2

1

2

3

4

(2)

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

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]

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

1

2

3

4

(3)

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]

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

1

2

3

4

(1)

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]

1
4
2
3

1

2

3

4

(4)

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)

1

2

3

4

(1)

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]

3
5
2
1

1

2

3

4

(1)

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]

(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.

Q 11 :

The 'Spin only' Magnetic moment for ${[Ni {({NH}_{3})}_{6}]}^{2 +}$ is ________ $\times 10^{- 1}$ BM (given = Atomic number of Ni : 28) [2024]

(28)

${[{Ni(NH}_{3})_{6}]}^{2 +}$

Oxidation number of Ni = +2

${Ni}^{2 +} : {}_{18}{[Ar]} 3 d^{8}$

Irrespective of strength of ligand, $3 d^{8}$ configuration after octahedral splitting becomes $t_{2 g}^{2, 2, 2} e_{g}^{1, 1}$ . It has two unpaired electrons $(n)$ ,

Spin only magnetic moment,

$μ = \sqrt{n (n + 2)} BM = \sqrt{2 (2 + 2)} BM = 2.83 BM$

$= 28.3 \times 10^{- 1} BM$

Q 12 :

Identify from the following species in which $d^{2} s p^{3}$ hybridization is shown by the central atom: [2024]

${[C o {(N H_{3})}_{6}]}^{3 +}$
$B r F_{5}$
${[Pt ({Cl}_{4})]}^{2 -}$
$S F_{6}$

1

2

3

4

(1)

For coordination number = 6, s and p block compounds always undergo ${sp}^{3} d^{2}$ hybridization.

${[C o {(N H_{3})}_{6}]}^{3 +}$

Oxidation number of Co = +3

Q 13 :

The molecule/ion with square pyramidal shape is [2024]

${[N i {(C N)}_{4}]}^{2 -}$
$P C l_{5}$
$B r F_{5}$
$P F_{5}$

1

2

3

4

(3)

Q 14 :

Consider the following complex ions [2024]

$P = {[{FeF}_{6}]}^{3 -}$

$Q = {[{V(H}_{2} O)_{6}]}^{2 +}$

$R = {[{Fe(H}_{2} {O)}_{6}]}^{2 +}$

The correct order of the complex ions, according to their spin-only magnetic moment values (in B.M.), is:

Q < P < R
R < P < Q
Q < R < P
R < Q < P

1

2

3

4

(3)

Spin only magnetic moment is given by the formula, $μ = \sqrt{n (n + 2)} B M$ , where $n$ is the number of unpaired electrons. Greater the number of unpaired electrons, more is the spin only magnetic moment.

${[F e F_{6}]}^{3 -}$

Oxidation number of Fe = +3

$F e^{3 +} = {}_{18}{[Ar] 3 d^{5}}$

As $F^{-}$ is a weak field ligand, splitting energy $(Δ_{0})$ is less than pairing energy (P). Hence, the fourth and fifth electrons prefer to go in $e_{g}$ orbital rather than undergoing pairing in $t_{2 g}$ orbital and $d^{5}$ configuration splits into $t_{2 g}^{3}, e_{g}^{2}$ . Thus, it has five unpaired electrons.

${[F e {(H_{2} O)}_{6}]}^{2 +}$

Oxidation number of Fe = +2

${Fe}^{2 +} = {}_{18}{[Ar] 3 d^{6}}$

As $H_{2} O$ is a weak field ligand, splitting energy $(Δ_{0})$ is less than pairing energy (P). Hence, the fourth and fifth electrons prefer to go in $e_{g}$ orbital rather than undergoing pairing in $t_{2 g}$ orbital and $d^{6}$ configuration split into $t_{2 g}^{4} e_{g}^{2}$ . Thus, it has four unpaired electrons.

${[V {(H_{2} O)}_{6}]}^{2 +}$

Oxidation number of V = +2

$V^{2 +} = {}_{18}{[Ar] 3 d^{3}}$

Irrespective of the ligand, $d^{3}$ complexes always split into $t_{2 g}^{3}, e_{g}^{0}$ and have three unpaired electrons.

Therefore, order of spin only magnetic moments is:

${[V {(H_{2} O)}_{6}]}^{2 +} < {[Fe {(H_{2} O)}_{6}]}^{2 +} < {[{FeF}_{6}]}^{3 -}$

Q 15 :

Match List I with List II [2024]

LIST I (Complex ion) LIST II (Electronic Configuration)

A. ${[Cr {(H_{2} O)}_{6}]}^{3 +}$ I. $t_{2 g}^{2} e_{g}^{0}$

B. ${[Fe(H_{2} O)_{6}]}^{3 +}$ II. $t_{2 g}^{3} e_{g}^{0}$

C. ${[Ni(H_{2} O)_{6}]}^{2 +}$ III. $t_{2 g}^{3} e_{g}^{2}$

D. ${[V(H_{2} O)_{6}]}^{3 +}$ IV. $t_{2 g}^{6} e_{g}^{2}$

Choose the correct answer from the options given below:

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

1

2

3

4

(2)

(A) ${[Cr {(H_{2} O)}_{6}]}^{3 +}$

Oxidation number of Cr = +3

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

$d^{3}$ complexes are always split into $t_{2 g}^{3}, e_{g}^{0}$ configuration irrespective of the field strength of the ligand.

(B) ${[Fe {(H ₂ O)}_{6}]}^{3 +}$

The oxidation number of Fe = +3

${Fe}^{3 +} = {}_{18}{[Ar] 3 d^{5}}$

As $H_{2} O$ is a weak field ligand, splitting energy $(Δ ₀)$ is less than pairing energy (P). $E . C = t_{2 g}^{3} e_{g}^{2}$

(C) ${[Ni {(H_{2} O)}_{6}]}^{2 +}$

Oxidation number of Ni = +2

${Ni}^{2 +} = {}_{18}{[Ar] 3 d^{8}}$

Irrespective of the ligand $d^{8}$ complexes always split into $t_{2 g}^{6}, e_{g}^{2}$

(D) ${[V(H_{2} O)_{6}]}^{3 +}$

Oxidation number of V = +3

$V^{3 +} = {}_{18}{[Ar] 3 d^{2}}$

$d^{2}$ complexes are always split into $t_{2 g}^{2}, e_{g}^{0}$ configuration irrespective of field strength of the ligand.

Q 16 :

Select the option with correct property - [2024]

$[Ni {(CO)}_{4}]$ and ${[{NiCl}_{4}]}^{2 -}$ both Paramagnetic
$[Ni {(CO)}_{4}]$ and ${[{NiCl}_{4}]}^{2 -}$ both Diamagnetic
$[Ni {(CO)}_{4}]$ Diamagnetic. ${[{NiCl}_{4}]}^{2 -}$ Paramagnetic
${[{NiCl}_{4}]}^{2 -}$ Diamagnetic. $[Ni {(CO)}_{4}]$ Paramagnetic

1

2

3

4

(3)

In ${[{NiCl}_{4}]}^{2 -}$ oxidation number of Ni = +2

${Ni}^{2 +} : {}_{18}{[Ar] 3 d^{8}}$

$C l^{-}$ is weak field ligand.

As it contains unpaired electrons, it is paramagnetic.

In $[Ni {(CO)}_{4}]$ oxidation number of Ni = 0

${}_{28}{Ni} = {}_{18}{[Ar] 3 d^{8} 4 s^{2}}$

CO is a strong field ligand.

As all electrons are paired, it is diamagnetic.

Q 17 :

Given below are two statements: [2024]

Statement (I): A solution of ${[Ni {(H_{2} O)}_{6}]}^{2 +}$ is green in colour.
Statement (II): A solution of ${[Ni {(CN)}_{4}]}^{2 -}$ is colourless.

In the light of the above statements, choose the most appropriate answer from the options given below:

Both Statement I and Statement II are incorrect
Both Statement I and Statement II are correct
Statement I is incorrect but Statement II is correct
Statement I is correct but Statement II is incorrect

1

2

3

4

(2)

${[Ni {(H_{2} O)}_{6}]}^{2 +}$

Oxidation number of Ni = +2

${Ni}^{2 +} = {}_{18}{[Ar] 3 d^{8}}$

Since coordination number of the complex is 6, it is an octahedral complex. Octahedral splitting of d orbitals is shown below:

Irrespective of the ligand, $d^{8}$ complexes always split into $t_{2 g}^{6}, e_{g}^{2}$ . From electronic configuration, it is clear that d-d transition can take place as $e_{g}$ orbitals are vacant. Because of this, ${[Ni {(H_{2} O)}_{6}]}^{2 +}$ is coloured. Magnitude of $Δ_{o}$ is such that red colour is absorbed during d-d transition of electron from $t_{2 g}$ to $e_{g}$ . Thus, complementary colour green is observed.

${[Ni {(CN)}_{4}]}^{2 -}$

Oxidation number of Ni = +2

${Ni}^{2 +} : {}_{18}{[Ar] 3 d^{8}}$

$C N^{-}$ is a strong field ligand and hence causes pairing of $3 d^{8}$ electrons.
As there is no vacant orbital, d-d transition cannot occur. Hence, this is a colourless complex.

Q 18 :

${[Co {({NH}_{3})}_{6}]}^{3 +}$ and ${[{CoF}_{6}]}^{3 -}$ are respectively known as: [2024]

Inner orbital Complex, Spin paired Complex
Spin paired Complex, Spin free Complex
Spin free Complex, Spin paired Complex
Outer orbital Complex, Inner orbital Complex

1

2

3

4

(2)

${[Co {({NH}_{3})}_{6}]}^{3 +}$

Oxidation number of Co = +3

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

${NH}_{3}$ is a strong field ligand. It pairs up d electrons. After pairing d electrons, two 3d orbitals are vacant. ${C o}^{3 +}$ undergoes $d^{2} s p^{3}$ hybridisation by using two 3d orbitals. Six $e^{-}$ pairs from six ${NH}_{3}$ are accommodated in these six $d^{2} s p^{3}$ orbitals.

As inner shell d orbitals (3d) are used for hybridisation, it is an inner orbital complex. Since it has a low number of unpaired electrons, it is a spin-paired complex.

${[{CoF}_{6}]}^{3 -}$

Oxidation number of Co = +3

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

$F^{-}$ is a weak field ligand. It cannot pair up d electrons. Thus, 4d orbitals are used for $s p^{3} d^{2}$ hybridisation. Six $e^{-}$ pairs from six $F^{-}$ are accommodated in these six $s p^{3} d^{2}$ orbitals.

Since outer orbital (4d) is used in hybridisation, it is an outer orbital complex. Since it has a high number of unpaired electrons, it is a spin-free complex.

Q 19 :

Consider the following complexes: [2024]

A. ${[CoCl {({NH}_{3})}_{5}]}^{2 +}$

B. ${[Co {(CN)}_{6}]}^{3 -}$

C. ${[Co {({NH}_{3})}_{5} (H_{2} O)]}^{3 +}$

D. ${[Cu {(H_{2} O)}_{4}]}^{2 +}$

The correct order of A, B, C, and D in terms of wave number of light absorbed is:

A < C < B < D
C < D < A < B
D < A < C < B
B < C < A < D

1

2

3

4

(3)

More is crystal field splitting energy, more is energy of photon $(\frac{h c}{λ})$ absorbed by the complex. More is energy of photon absorbed, more is wavenumber $(\frac{1}{λ})$ absorbed.
Tetrahedral splitting is less than octahedral splitting. Thus ${[Cu {(H_{2} O)}_{4}]}^{2 +}$ absorbs photon of least wavenumber.
Order of field strength of given ligands is: ${Cl}^{-} < H_{2} O < {NH}_{3} < {CN}^{- 1}$ . Strong field ligands cause more splitting, thus order of splitting and order of wavenumber absorbed is:
${[CoCl {({NH}_{3})}_{5}]}^{2 +} (A) < {[Co {({NH}_{3})}_{5} (H_{2} O)]}^{3 +} (C) < {[Co {(CN)}_{6}]}^{3 -} (B)$

Q 20 :

Match List-I with List-II [2024]

List-I (Complex ion): List-II (Spin only magnetic moment in B.M.)

(A) ${[Cr {({NH}_{3})}_{6}]}^{3 +}$ (I) 4.90

(B) ${[{NiCl}_{4}]}^{2 -}$ (II) 3.87

(C) ${[{CoF}_{6}]}^{3 -}$ (III) 0.0

(D) ${[Ni {(CN)}_{4}]}^{2 -}$ (IV) 2.83

Choose the correct answer from the options given below:

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

1

2

3

4

(3)

(A) ${[Cr {({NH}_{3})}_{6}]}^{3 +}$

Oxidation number of Cr = +3

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

As inner d orbitals are available, it undergoes $d^{2} s p^{3}$ hybridization.

Orbital diagram of ${Cr}^{3 +}$ in presence of ${NH}_{3}$

It has 3 unpaired electrons. Spin only magnetic moment $(μ) = \sqrt{n (n + 2)} B M = \sqrt{3 (3 + 2)} B M = 3.87 B M$

(B) ${[{NiCl}_{4}]}^{2 -}$

Oxidation number of Ni = +2

${Ni}^{2 +} = {}_{18}{[Ar] 3 d^{8}}$

${Cl}^{-}$ is weak field ligand hence does not cause pairing of $3 d^{8}$ electrons, ${Ni}^{2 +}$ undergoes $s p^{3}$ hybridization and lone pairs from ${Cl}^{-}$ are accommodated in $s p^{3}$ orbitals.

Orbital diagram of ${Ni}^{2 +}$ in presence of ${Cl}^{-}$

As it contains 2 unpaired electrons. Spin only magnetic moment $(μ) = \sqrt{n (n + 2)} B M = \sqrt{2 (2 + 2)} B M = 2.82 B M$

(C) ${[{CoF}_{6}]}^{3 -}$

Oxidation number of Co = +3

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

$F^{-}$ is a weak field ligand. It cannot pair up d electrons. Thus, 4d orbitals are used for $s p^{3} d^{2}$ hybridization. Six $e^{-}$ pairs from six $F^{-}$ are accommodated in these six $s p^{3} d^{2}$ orbitals.

Orbital diagram of ${Co}^{3 +}$ in presence of $F^{-}$

It has 4 unpaired electrons. Spin only magnetic moment $(μ) = \sqrt{n (n + 2)} B M = \sqrt{4 (4 + 2)} B M = 4.9 B M$

(D) ${[Ni {(CN)}_{4}]}^{2 -}$

Oxidation number of Ni = +2

${Ni}^{2 +} = {}_{18}{[Ar] 3 d^{8}}$

${CN}^{-}$ is strong field ligand hence causes pairing of $3 d^{8}$ electrons, then causes $d s p^{2}$ hybridization using 3d, 4s, and 4p orbitals.

Orbital diagram of $N i^{2 +}$ in presence of $C N^{-}$

It has no unpaired electron. Spin only magnetic moment $(μ) = \sqrt{n (n + 2)} B M = \sqrt{0 (0 + 2)} B M = 0 B M$

Q 21 :

From the magnetic behaviour of ${[{NiCl}_{4}]}^{2 -}$ (paramagnetic) and $[Ni {(CO)}_{4}]$ (diamagnetic), choose the correct geometry and oxidation state. [2025]

${[{NiCl}_{4}]}^{2 -} : {Ni}^{II}, tetrahedral$

$[Ni {(CO)}_{4}] : {Ni}^{II}, square planar$
${[{NiCl}_{4}]}^{2 -} : {Ni}^{II}, tetrahedral$

$[Ni {(CO)}_{4}] : Ni (0), tetrahedral$
${[{NiCl}_{4}]}^{2 -} : {Ni}^{II}, square planar$

$[Ni {(CO)}_{4}] : Ni (0), square planar$
${[{NiCl}_{4}]}^{2 -} : Ni (0), tetrahedral$

$[Ni {(CO)}_{4}] : Ni (0), square planar$

1

2

3

4

(2)

In ${[{NiCl}_{4}]}^{2 -},$

Oxidation number of Ni = +2

${}_{28}{Ni} : {}_{18}{[Ar]}$ $3 d^{8} 4 s^{2}$

${Ni}^{2 +} : {}_{18}{[Ar]}$ $3 d^{8}$

In $[Ni {(CO)}_{4}],$

Oxidation number of Ni = 0

${}_{28}{Ni} = {}_{18}{[Ar]}$ $3 d^{8} 4 s^{2}$

CO being a strong field ligand pushes 4s electrons into $3 d^{8}$ orbitals.

Q 22 :

In which of the following complexes the CFSE, $Δ_{o}$ will be equal to zero? [2025]

$[Fe {(en)}_{3}] {Cl}_{3}$
$[Fe {({NH}_{3})}_{6}] {Br}_{2}$
$K_{3} [Fe {(SCN)}_{6}]$
$K_{4} [Fe {(CN)}_{6}]$

1

2

3

4

(3)

Complex	Ion	Ligand type	Electronic configuration of ion after octahedral splitting	CFSE
$[Fe {(en)}_{3}] {Cl}_{3}$	${Fe}^{3 +} ({}_{18}{[Ar]} 3 d^{5})$	Strong field	$t_{2 g}^{2, 2, 1} e_{g}^{0, 0}$	$5 \times (- 0.4 Δ_{0}) + 2 P$
$[Fe {({NH}_{3})}_{6}] {Br}_{2}$	${Fe}^{2 +} ({}_{18}{[Ar]} 3 d^{6})$	Strong field	$t_{2 g}^{2, 2, 2} e_{g}^{0, 0}$	$6 \times (- 0.4 Δ_{0}) + 2 P$
$K_{3} [Fe {(SCN)}_{6}]$	${Fe}^{3 +} ({}_{18}{[Ar]} 3 d^{5})$	Weak field	$t_{2 g}^{1, 1, 1} e_{g}^{1, 1}$	$3 \times (- 0.4 Δ_{0}) + 2 \times 0.6 Δ_{0} = 0$
$K_{4} [Fe {(CN)}_{6}]$	${Fe}^{2 +} ({}_{18}{[Ar]} 3 d^{6})$	Strong field	$t_{2 g}^{2, 2, 1} e_{g}^{0, 0}$	$6 \times (- 0.4 Δ_{0}) + 2 P$

Q 23 :

Identify the homoleptic complex(es) that is/are low spin. [2025]

(A) ${[Fe {(CN)}_{5} NO]}^{2 -}$
(B) ${[{CoF}_{6}]}^{3 -}$
(C) ${[Fe {(CN)}_{6}]}^{4 -}$
(D) ${[Co {({NH}_{3})}_{6}]}^{3 +}$
(E) ${[Cr {(H_{2} O)}_{6}]}^{2 +}$

(C) and (D) only
(B) and (E) only
(C) only
(A) and (C) only

1

2

3

4

(1)

Homoleptic complexes in which a metal is bound to only one kind of donor groups. B, C, D and E are homoleptic. Low spin complexes are formed by metal ions with $d^{4}$ to $d^{7}$ configurations that are bound to strong field ligands. As $F^{-}$ and $H_{2} O$ are weak field ligands, (B) and (E) are high spin complexes. $C N^{-}$ and $N H_{3}$ are strong field ligands, so (C) (which has ${Fe}^{2 +} = {}_{18}{[Ar]}$ $3 d^{6}$ ) and (D) (which has $C o^{3 +} = {}_{18}{[Ar]}$ $3 d^{6}$ ) are low spin complexes.

Heteroleptic complexes in which a metal is bound to more than one kind of donor groups. A is heteroleptic.

Q 24 :

The correct order of the following complexes in terms of their crystal field stabilization energies is : [2025]

${[Co {({NH}_{3})}_{4}]}^{2 +} < {[Co {({NH}_{3})}_{6}]}^{2 +} < {[Co {({NH}_{3})}_{6}]}^{3 +} < {[Co {(en)}_{3}]}^{3 +}$
${[Co {({NH}_{3})}_{4}]}^{2 +} < {[Co {({NH}_{3})}_{6}]}^{2 +} < {[Co {(en)}_{3}]}^{3 +} < {[Co {({NH}_{3})}_{6}]}^{3 +}$
${[Co {(en)}_{3}]}^{3 +} < {[Co {({NH}_{3})}_{6}]}^{3 +} < {[Co {({NH}_{3})}_{6}]}^{2 +} < {[Co {({NH}_{3})}_{4}]}^{2 +}$
${[Co {({NH}_{3})}_{6}]}^{2 +} < {[Co {({NH}_{3})}_{6}]}^{3 +} < {[Co {({NH}_{3})}_{4}]}^{2 +} < {[Co {(en)}_{3}]}^{3 +}$

1

2

3

4

(1)

Complex	Electronic configuration of central ion before octahedral splitting	Electronic configuration of central ion after octahedral splitting	CFSE
${[Co {({NH}_{3})}_{6}]}^{2 +}$	${Co}^{2 +} =_{18} [Ar]$ $3 d^{7} 4 s^{0}$	$t_{2 g}^{2, 2, 2} e_{g}^{1, 0}$	$6 \times (- 0.4 Δ_{0}) + 1 \times (0.6 Δ_{0}) + P = - 1.8 Δ_{0} + P$
${[{Co(NH}_{3})_{6}]}^{3 +}$	${Co}^{3 +} =_{18} [Ar]$ $3 d^{6} 4 s^{0}$	$t_{2 g}^{2, 2, 2} e_{g}^{0, 0}$	$6 \times (- 0.4 Δ_{0}) + 0 \times (0.6 Δ_{0}) + 2 P = - 2.4 Δ_{0} + 2 P$
${[Co(en)_{3}]}^{3 +}$	${Co}^{3 +} =_{18} [Ar]$ $3 d^{6} 4 s^{0}$	$t_{2 g}^{2, 2, 2} e_{g}^{0, 0}$	$6 \times (- 0.4 Δ_{0}) + 0 \times (0.6 Δ_{0}) + 2 P = - 2.4 Δ_{0} + 2 P$

As en is a stronger ligand than $N H_{3}$ , CFSE of ${[Co {(en)}_{3}]}^{3 +}$ is more than that of ${[Co {({NH}_{3})}_{6}]}^{3 +}$ . For octahedral complexes, order of CFSE is:

${[Co {({NH}_{3})}_{6}]}^{2 +} < {[Co {({NH}_{3})}_{6}]}^{3 +} < {[Co(en)_{3}]}^{3 +} . {[Co {({NH}_{3})}_{4}]}^{2 +}$ is a square planar complex and we need not to find its CFSE to attempt this question.

The only option where order of CFSE given is ${[Co {({NH}_{3})}_{6}]}^{2 +} < {[Co {({NH}_{3})}_{6}]}^{3 +} < {[Co(en)_{3}]}^{3 +}$ is option 1.

Q 25 :

The $d$ -electronic configuration of an octahedral Co(II) complex having magnetic moment of 3.95 BM is : [2025]

$t_{2 g}^{3} e_{g}^{0}$
$t_{2 g}^{5} e_{g}^{2}$
$e_{g}^{4} t_{2 g}^{3}$
$t_{2 g}^{6} e_{g}^{1}$

1

2

3

4

(2)

Magnetic moment ( $μ$ ) = $\sqrt{n (n + 2)}$ BM = 3.95 BM, where $n$ = number of unpaired electrons.

This gives $n = 3$ .

Electronic configuration of $C o^{2 +}$ is ${}_{18}{[Ar]}$ $3 d^{7}$ , which splits into $t_{2 g}^{2, 2, 2} e_{g}^{1, 0} (for strong field ligand) or t_{2 g}^{2, 2, 1} e_{g}^{1, 1} (for weak field ligand) .$ $t_{2 g}^{2, 2, 1} e_{g}^{1, 1}$ has three unpaired electrons; hence, this is the correct answer.

Q 26 :

When Ethane-1,2-diamine is added progressively to an aqueous solution of Nickel(II) chloride, the sequence of colour change observed will be: [2025]

Pale Blue → Blue → Green → Violet
Violet → Blue → Pale Blue → Green
Pale Blue → Blue → Violet → Green
Green → Pale Blue → Blue → Violet

1

2

3

4

(4)

$\begin{matrix} \underset{Green}{{[Ni(H_{2} O)_{6}]}^{2 +} (aq)} \underset{Pale blue}{\overset{en}{\to} {[Ni(H_{2} O)_{4} (en)]}^{2 +} (aq)} \end{matrix}$ $\overset{en}{\to}$ $\underset{Blue}{{[{Ni(H}_{2} {O)}_{2} {(en)}_{2}]}^{2 +} (aq)} \underset{Violet}{\overset{en}{\to} {[Ni(en)_{3}]}^{2 +} (aq)}$

Q 27 :

The conditions and consequence that favours the $t_{2 g}^{3} e_{g}^{1}$ configuration in a metal complex are: [2025]

weak field ligand, low spin complex
strong field ligand, high spin complex
weak field ligand, high spin complex
strong field ligand, low spin complex

1

2

3

4

(3)

For weak field ligand, $Δ_{o} < P$ , so the fourth electron prefers to overcome the $Δ_{o}$ energy barrier and go to $e_{g}$ , rather than overcoming pairing energy barrier (P) and going to $t_{2 g}$ . Hence, for weak field ligand, configuration splits as $t_{2 g}^{1, 1, 1} e_{g}^{1, 0}$ (high spin complex) in octahedral field. For strong field ligand, $d^{4}$ configuration splits as $t_{2 g}^{2, 1, 1} e_{g}^{0, 0}$ (low spin complex) in octahedral field.

Q 28 :

The correct increasing order of stability of the complexes based on $Δ_{0}$ value is: [2025]

I. ${[Mn {(CN)}_{6}]}^{3 -}$
II. ${[Co {(CN)}_{6}]}^{4 -}$
III. ${[Fe {(CN)}_{6}]}^{4 -}$
IV. ${[Fe {(CN)}_{6}]}^{3 -}$

II < III < I < IV
III < II < IV < I
I < II < IV < III
IV < III < II < I

1

2

3

4

(3)

S.no	Complex	Electronic configuration of central metal ion before splitting	Electronic configuration of central metal ion after splitting	CFSE
I	${[Mn {(CN)}_{6}]}^{3 -}$	${Mn}^{3 +} = {}_{18}{[Ar]}$ $3 d^{4}$	$t_{2 g}^{2, 1, 1} e_{g}^{0, 0}$	$4 \times (- 0.4 Δ_{o}) + P = - 16 Δ_{o} + P$
II	${[Co {(CN)}_{6}]}^{4 -}$	${Co}^{2 +} = {}_{18}{[Ar]}$ $3 d^{7}$	$t_{2 g}^{2, 2, 2} e_{g}^{1, 0}$	$6 \times (- 0.4 Δ_{o}) + 1 \times (0.6 Δ_{o}) + P = - 1.8 Δ_{o} + P$
III	${[Fe {(CN)}_{6}]}^{4 -}$	${Fe}^{2 +} = {}_{18}{[Ar]}$ $3 d^{6}$	$t_{2 g}^{2, 2, 2} e_{g}^{0, 0}$	$6 \times (- 0.4 Δ_{o}) + 2 P = - 2.4 Δ_{o} + P$
IV	${[Fe {(CN)}_{6}]}^{3 -}$	${Fe}^{3 +} = {}_{18}{[Ar]}$ $3 d^{5}$	$t_{2 g}^{2, 2, 1} e_{g}^{0, 0}$	$5 \times (- 0.4 Δ_{o}) + 2 P = - 2.0 Δ_{o} + P$

More negative is CFSE, more is stability.

Q 29 :

The calculated spin-only magnetic moments of $K_{3} [Fe {(OH)}_{6}]$ and $K_{4} [Fe {(OH)}_{6}]$ respectively are: [2025]

5.92 and 4.90 B.M.
4.90 and 4.90 B.M.
4.90 and 5.92 B.M.
3.87 and 4.90 B.M.

1

2

3

4

(1)

Complex	Electronic configuration of central metal ion before octahedral splitting	Electronic configuration of central metal ion after octahedral splitting	Number of unpaired electrons (n)	Spin-only magnetic moment ( $μ$ =)
$K_{3} {[Fe(OH)}_{6}]$	${Fe}^{3 +} = {}_{18}{[Ar]}$ $3 d^{5}$	$t_{2 g}^{1, 1, 1} e_{g}^{1, 1}$	5	$\sqrt{5 (5 + 2)} BM = 5.92 BM$
$K_{4} [{Fe(OH)}_{6}]$	${Fe}^{2 +} = {}_{18}{[Ar]}$ $3 d^{6}$	$t_{2 g}^{2, 1, 1} e_{g}^{1, 1}$	4	$\sqrt{4 (4 + 2)} BM = 4.9 BM$

Q 30 :

Given below are two statements: [2025]

Statement (I): In octahedral complexes, when $Δ_{o}$ < P high spin complexes are formed. When $Δ_{o}$ > P low spin complexes are formed.

Statement (II): In tetrahedral complexes because of $Δ_{t}$ < P, low spin complexes are rarely formed.

In the light of the above statements, choose the most appropriate answer from the options given below:

Statement I is correct but Statement II is incorrect
Both Statement I and Statement II are incorrect
Statement I is incorrect but Statement II is correct
Both Statement I and Statement II are correct

1

2

3

4

(4)

Statement I:

Statement II:

$Δ_{t} = \frac{4}{9} Δ_{0} < P,$ so low spin complexes are rarely formed for tetrahedral complexes.

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]

Q 11 :

The 'Spin only' Magnetic moment for ${[Ni {({NH}_{3})}_{6}]}^{2 +}$ is ________ $\times 10^{- 1}$ BM (given = Atomic number of Ni : 28) [2024]

Q 12 :

Identify from the following species in which $d^{2} s p^{3}$ hybridization is shown by the central atom: [2024]

Q 13 :

The molecule/ion with square pyramidal shape is [2024]

Q 14 :

Consider the following complex ions [2024]

$P = {[{FeF}_{6}]}^{3 -}$

$Q = {[{V(H}_{2} O)_{6}]}^{2 +}$

$R = {[{Fe(H}_{2} {O)}_{6}]}^{2 +}$

The correct order of the complex ions, according to their spin-only magnetic moment values (in B.M.), is:

Q 16 :

Select the option with correct property - [2024]

Q 18 :

${[Co {({NH}_{3})}_{6}]}^{3 +}$ and ${[{CoF}_{6}]}^{3 -}$ are respectively known as: [2024]

Q 19 :

Consider the following complexes: [2024]

A. ${[CoCl {({NH}_{3})}_{5}]}^{2 +}$

B. ${[Co {(CN)}_{6}]}^{3 -}$

C. ${[Co {({NH}_{3})}_{5} (H_{2} O)]}^{3 +}$

D. ${[Cu {(H_{2} O)}_{4}]}^{2 +}$

The correct order of A, B, C, and D in terms of wave number of light absorbed is:

Q 21 :

From the magnetic behaviour of ${[{NiCl}_{4}]}^{2 -}$ (paramagnetic) and $[Ni {(CO)}_{4}]$ (diamagnetic), choose the correct geometry and oxidation state. [2025]

Q 22 :

In which of the following complexes the CFSE, $Δ_{o}$ will be equal to zero? [2025]

Q 23 :

Identify the homoleptic complex(es) that is/are low spin. [2025]

(A) ${[Fe {(CN)}_{5} NO]}^{2 -}$
(B) ${[{CoF}_{6}]}^{3 -}$
(C) ${[Fe {(CN)}_{6}]}^{4 -}$
(D) ${[Co {({NH}_{3})}_{6}]}^{3 +}$
(E) ${[Cr {(H_{2} O)}_{6}]}^{2 +}$

Q 24 :

The correct order of the following complexes in terms of their crystal field stabilization energies is : [2025]

Q 25 :

The $d$ -electronic configuration of an octahedral Co(II) complex having magnetic moment of 3.95 BM is : [2025]

Q 26 :

When Ethane-1,2-diamine is added progressively to an aqueous solution of Nickel(II) chloride, the sequence of colour change observed will be: [2025]

Q 27 :

The conditions and consequence that favours the $t_{2 g}^{3} e_{g}^{1}$ configuration in a metal complex are: [2025]

Q 28 :

The correct increasing order of stability of the complexes based on $Δ_{0}$ value is: [2025]

I. ${[Mn {(CN)}_{6}]}^{3 -}$
II. ${[Co {(CN)}_{6}]}^{4 -}$
III. ${[Fe {(CN)}_{6}]}^{4 -}$
IV. ${[Fe {(CN)}_{6}]}^{3 -}$

Q 29 :

The calculated spin-only magnetic moments of $K_{3} [Fe {(OH)}_{6}]$ and $K_{4} [Fe {(OH)}_{6}]$ respectively are: [2025]

Want Us to Email you About Special Offers & Updates?

	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.	$e^{2}, t_{2}^{3}$

	LIST I (Complex ion)		LIST II (Electronic Configuration)
A.	${[Cr {(H_{2} O)}_{6}]}^{3 +}$	I.	$t_{2 g}^{2} e_{g}^{0}$
B.	${[Fe(H_{2} O)_{6}]}^{3 +}$	II.	$t_{2 g}^{3} e_{g}^{0}$
C.	${[Ni(H_{2} O)_{6}]}^{2 +}$	III.	$t_{2 g}^{3} e_{g}^{2}$
D.	${[V(H_{2} O)_{6}]}^{3 +}$	IV.	$t_{2 g}^{6} e_{g}^{2}$

	List-I (Complex ion):		List-II (Spin only magnetic moment in B.M.)
(A)	${[Cr {({NH}_{3})}_{6}]}^{3 +}$	(I)	4.90
(B)	${[{NiCl}_{4}]}^{2 -}$	(II)	3.87
(C)	${[{CoF}_{6}]}^{3 -}$	(III)	0.0
(D)	${[Ni {(CN)}_{4}]}^{2 -}$	(IV)	2.83

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]

Q 11 : The 'Spin only' Magnetic moment for [Ni(NH3)6]2+ is ________ ×10-1 BM (given = Atomic number of Ni : 28) [2024]

Q 12 : Identify from the following species in which d2sp3 hybridization is shown by the central atom: [2024]

Q 13 : The molecule/ion with square pyramidal shape is [2024]

Q 14 : Consider the following complex ions [2024] P=[FeF6]3- Q=[V(H2O)6]2+ R=[Fe(H2O)6]2+ The correct order of the complex ions, according to their spin-only magnetic moment values (in B.M.), is:

Q 15 : Match List I with List II [2024] LIST I (Complex ion) LIST II (Electronic Configuration) A. [Cr(H2O)6]3+ I. t2g2eg0 B. [Fe(H2O)6]3+ II. t2g3eg0 C. [Ni(H2O)6]2+ III. t2g3eg2 D. [V(H2O)6]3+ IV. t2g6eg2 Choose the correct answer from the options given below:

Q 16 : Select the option with correct property - [2024]

Q 17 : Given below are two statements: [2024] Statement (I): A solution of [Ni(H2O)6]2+ is green in colour. Statement (II): A solution of [Ni(CN)4]2- is colourless. In the light of the above statements, choose the most appropriate answer from the options given below:

Q 18 : [Co(NH3)6]3+ and [CoF6]3- are respectively known as: [2024]

Q 19 : Consider the following complexes: [2024] A. [CoCl(NH3)5]2+ B. [Co(CN)6]3- C. [Co(NH3)5(H2O)]3+ D. [Cu(H2O)4]2+ The correct order of A, B, C, and D in terms of wave number of light absorbed is:

Q 20 : Match List-I with List-II [2024] List-I (Complex ion): List-II (Spin only magnetic moment in B.M.) (A) [Cr(NH3)6]3+ (I) 4.90 (B) [NiCl4]2- (II) 3.87 (C) [CoF6]3- (III) 0.0 (D) [Ni(CN)4]2- (IV) 2.83 Choose the correct answer from the options given below:

Q 21 : From the magnetic behaviour of [NiCl4]2- (paramagnetic) and [Ni(CO)4] (diamagnetic), choose the correct geometry and oxidation state. [2025]

Q 22 : In which of the following complexes the CFSE, Δo will be equal to zero? [2025]

Q 23 : Identify the homoleptic complex(es) that is/are low spin. [2025] (A) [Fe(CN)5NO]2- (B) [CoF6]3- (C) [Fe(CN)6]4- (D) [Co(NH3)6]3+ (E) [Cr(H2O)6]2+

Q 24 : The correct order of the following complexes in terms of their crystal field stabilization energies is : [2025]

Q 25 : The d-electronic configuration of an octahedral Co(II) complex having magnetic moment of 3.95 BM is : [2025]

Q 26 : When Ethane-1,2-diamine is added progressively to an aqueous solution of Nickel(II) chloride, the sequence of colour change observed will be: [2025]

Q 27 : The conditions and consequence that favours the t2g3eg1 configuration in a metal complex are: [2025]

Q 28 : The correct increasing order of stability of the complexes based on Δ0 value is: [2025] I. [Mn(CN)6]3- II. [Co(CN)6]4- III. [Fe(CN)6]4- IV. [Fe(CN)6]3-

Q 29 : The calculated spin-only magnetic moments of K3[Fe(OH)6] and K4[Fe(OH)6] respectively are: [2025]

Want Us to Email you About Special Offers & Updates?

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]

Q 11 :

The 'Spin only' Magnetic moment for ${[Ni {({NH}_{3})}_{6}]}^{2 +}$ is ________ $\times 10^{- 1}$ BM (given = Atomic number of Ni : 28) [2024]

Q 12 :

Identify from the following species in which $d^{2} s p^{3}$ hybridization is shown by the central atom: [2024]

Q 13 :

The molecule/ion with square pyramidal shape is [2024]

Q 14 :

Consider the following complex ions [2024]

$P = {[{FeF}_{6}]}^{3 -}$

$Q = {[{V(H}_{2} O)_{6}]}^{2 +}$

$R = {[{Fe(H}_{2} {O)}_{6}]}^{2 +}$

The correct order of the complex ions, according to their spin-only magnetic moment values (in B.M.), is:

Q 16 :

Select the option with correct property - [2024]

Q 18 :

${[Co {({NH}_{3})}_{6}]}^{3 +}$ and ${[{CoF}_{6}]}^{3 -}$ are respectively known as: [2024]

Q 19 :

Consider the following complexes: [2024]

A. ${[CoCl {({NH}_{3})}_{5}]}^{2 +}$

B. ${[Co {(CN)}_{6}]}^{3 -}$

C. ${[Co {({NH}_{3})}_{5} (H_{2} O)]}^{3 +}$

D. ${[Cu {(H_{2} O)}_{4}]}^{2 +}$

The correct order of A, B, C, and D in terms of wave number of light absorbed is:

Q 21 :

From the magnetic behaviour of ${[{NiCl}_{4}]}^{2 -}$ (paramagnetic) and $[Ni {(CO)}_{4}]$ (diamagnetic), choose the correct geometry and oxidation state. [2025]

Q 22 :

In which of the following complexes the CFSE, $Δ_{o}$ will be equal to zero? [2025]

Q 23 :

Identify the homoleptic complex(es) that is/are low spin. [2025]

(A) ${[Fe {(CN)}_{5} NO]}^{2 -}$
(B) ${[{CoF}_{6}]}^{3 -}$
(C) ${[Fe {(CN)}_{6}]}^{4 -}$
(D) ${[Co {({NH}_{3})}_{6}]}^{3 +}$
(E) ${[Cr {(H_{2} O)}_{6}]}^{2 +}$

Q 24 :

The correct order of the following complexes in terms of their crystal field stabilization energies is : [2025]

Q 25 :

The $d$ -electronic configuration of an octahedral Co(II) complex having magnetic moment of 3.95 BM is : [2025]

Q 26 :

When Ethane-1,2-diamine is added progressively to an aqueous solution of Nickel(II) chloride, the sequence of colour change observed will be: [2025]

Q 27 :

The conditions and consequence that favours the $t_{2 g}^{3} e_{g}^{1}$ configuration in a metal complex are: [2025]

Q 28 :

The correct increasing order of stability of the complexes based on $Δ_{0}$ value is: [2025]

I. ${[Mn {(CN)}_{6}]}^{3 -}$
II. ${[Co {(CN)}_{6}]}^{4 -}$
III. ${[Fe {(CN)}_{6}]}^{4 -}$
IV. ${[Fe {(CN)}_{6}]}^{3 -}$

Q 29 :

The calculated spin-only magnetic moments of $K_{3} [Fe {(OH)}_{6}]$ and $K_{4} [Fe {(OH)}_{6}]$ respectively are: [2025]