Coordination Compounds — Page 3 | JEE Chemistry

Q21

Match the LIST-I with LIST-IILIST-I (Complex/ Species)LIST-II (Shape & magnetic moment)A. [Ni(CO)4]I. Tetrahedral, 2.8 BMB. [Ni(CN)4]2–II. Square planar, 0 BMC. [NiCl4]2–III. Tetrahedral, 0 BMD. [MnBr4]2–IV. Tetrahedral, 5.9 BMChoose the correct answer from the options given below:

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

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

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

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

Correct Answer

Option C

Solution

(A) $\left[\mathrm{Ni}(\mathrm{CO})_4\right], \mathrm{Ni}^0:[\mathrm{Ar}] 3 \mathrm{~d}^8 4 \mathrm{~s}^2$ Valence orbitals of $\mathrm{Ni}^0$ in pre-hybridisation state : Tetrahedral, Diamagnetic, $\mu=0$ B.M.

(B) $\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}, \mathrm{Ni}^{+2}:[\mathrm{Ar}] 3 \mathrm{~d}^8 4 \mathrm{~s}^0$ Valence orbitals of $\mathrm{Ni}^{+2}$ in pre-hybridisation state : Square planar, Diamagnetic, $\mu=0$ B.M.

(C) $\left[\mathrm{NiCl}_4\right]^{2-}, \mathrm{Ni}^{+2}:[\mathrm{Ar}] 3 \mathrm{~d}^8 4 \mathrm{~s}^0$ Valence orbitals of $\mathrm{Ni}^{+2}$ in ground state : Tetrahedral, paramagnetic, $\mu=\sqrt{8}=2.8$ B.M.

(D) $\left[\mathrm{MnBr}_4\right]^{2-}, \mathrm{Mn}^{+2}:[\mathrm{Ar}] 3 \mathrm{~d}^5$ Valence orbitals of $\mathrm{Mn}^{+2}$ in ground state : Tetrahedral, paramagnetic, $\mu=\sqrt{35}=5.9$ B.M.

Q22

Which one of the following complexes shows optical isomerism? (en = ethylenediamine)

A cis[Co(en)2Cl2]Cl

B trans[Co(en)2Cl2]Cl

C [Co(NH3)4Cl2]Cl

D [Co(NH3)3Cl3]

Correct Answer

Option A

Solution

Optical isomerism occurs when a molecule is non-superimposable with its mirror image hence the complex

cis - \left[ {Co{{\left( {en} \right)}_2}C{l_2}} \right]Cl

is optically active.

Q23

The coordination geometry around the manganese in decacarbonyldimanganese

(0)

is

A Trigonal bipyramidal

B Square pyramidal

C Square planar

D Octahedral

Correct Answer

Option D

Solution

\mathrm{Mn_2(CO)_{10}}

Q24

Which one of the following complexes will consume more equivalents of aqueous solution of Ag(NO3)?

A Na3[CrCl6]

B [Cr(H2O)5Cl]Cl2

C [Cr(H2O)6]Cl3

D Na2[CrCl5(H2O)]

Correct Answer

Option C

Solution

[Cr(H2O)6]Cl3 has the highest primary valency among the given complexes, that is, three, therefore, it will consume three moles of AgNO3 and precipitate three moles of AgCl.

[Cr(H2O)6]Cl3 + 3AgNo3 $\to$ 3AgCl + [Cr(H2O)6](NO)3

Q25

Coordination compound have great importance in biological systems. In this context which of the following statements is incorrect?

A Chlorophylls are green pigments in plants and contains calcium

B Carboxypeptidase – A is an enzyme and contains zinc

C Cyanocobalamin is B12 and contains cobalt

D Haemoglobin is the red pigment of blood and contains iron

Correct Answer

Option A

Solution

The chlorophyll molecule plays an important role in photosynthesis, contain porphyrin ring and the metal

Mg

not

Ca.

Q26

Which of the following is an example of homoleptic complex?

A [Co(NH3)6]Cl3

B [Pt(NH3)2Cl2]

C [Co(NH3)4Cl2]

D [Co(NH3)5Cl]Cl2

Correct Answer

Option A

Solution

Homoleptic complexes are those compounds in which all the ligands bound to the central metal are identical.

Thus, these types of complexes have only one type of ligands.

In the complex [Co(NH3)6]Cl3 , central atom Co has ammonia ligands as all six.

Heteroleptic complexes are those compounds in which central transition metal has more than one type of ligands.

So, rest of the options are examples of heteroleptic complexes.

Q27

Which one the following has largest number of isomers? (R = alkyl group, en = ethylenediamine)

A [Ru(NH3)4Cl2]+

B [Co(en)2Cl2]+

C [Ir(PR3)2 H(CO)]2+

D [Co(NH3)5Cl]2+

Correct Answer

Option B

Solution

Isomers

Q28

The most stable ion is :

A [Fe(OH)3]3-

B [Fe(Cl)6]3-

C [Fe(CN)6]3-

D [Fe(H2O)6]3+

Correct Answer

Option C

Solution

The cyano and hydroxo complexes are far more stable than those formed by halide ion. This is due to the fact that

C{N^ - }

and

O{H^ - }

are strong lewis bases (nucleophiles). Further

{\left[ {Fe{{\left( {OH} \right)}_5}} \right]^{3 - }}

is not formed. hence most stable ion is

{\left[ {Fe{{\left( {CN} \right)}_6}} \right]^{3 - }}

Q29

CH3 - Mg - Br is an organometallic compound due to :

A Mg - Br bond

B C - Mg bond

C C - Br bond

D C - H bond

Correct Answer

Option B

Solution

Compounds that contain at least one carbon metal bond are known as organometallic compounds. In

C{H_3}

- Mg - Br

(Grignard's reagent) a bond is present between carbon and

Mg

(Metal) hence it is an organometallic compound.

Q30

Which of the following facts about the complex [Cr (NH3)6 ]Cl3 is wrong?

A The complex is paramagnetic

B The complex is an outer orbital complex

C The complex gives white precipitate with silver nitrate solution

D The complex involves d2sp3 hybridization and is octahedral in shape.

Correct Answer

Option B

Solution

\left[ {Cr{{\left( {N{H_3}} \right)}_6}} \right]C{l_3}\,\,

is an inner orbital complex, because in this complex

d-

orbital used is of lower quantum number i.e.

(n-1).

It results from

{d^2}\,\,\,

s{p^3}

(inner orbital) hybridization.