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(iv) [Cr(H₂O)₆]Cl₃

The number of moles of AgCl formed will depend upon the number of Chloride ions available in the coordinate compound. The number of Chloride ions satisfying the primary valency will only react with AgNO₃ to produce AgCl.  

[CoCl(NH₃)₅]Cl₂ + AgNO₃ → 2 AgCl 

Thus, 2 moles of AgCl will be formed.

• Optical isomerism is exhibited by those coordination compounds which possess chirality. 
• There should not be the presence of element of symmetry which makes the complex optically inactive. 
• The mirror images of the complex molecule or ion must be non-superimposable with the molecule or ion. B 

The ligands are then classified as (a) strong field and (b) weak field ligands. Strong field ligands are those in which donor atoms are C, N or P. Thus CN^-, NC^-, CO, HN₃, EDTA, en (ethylenediammine) are considered to be strong ligands. They cause larger splitting of d orbitals and pairing of electrons is favoured. These ligands tend to form low spin complexes. Weak field ligands are those in which donor atoms are halogens, oxygen or sulphur.

For example,

F^-, CI^-, Br^-, I^-, SCN^-, C₂O₄^2-. In case of these ligands the A0 parameter is smaller compared to the energy required for the pairing of electrons, which is called as electron pairing energy. The ligands then can be arranged in order of their increasing field strength as

I^- < Br^- < CI^- < S^2- < F^- < OH^- < C₂O₄^2- < H₂O < NCS < EDTA < NH₃ < en < CN^- < CO.

This is because if AgNO₃ is used Cu will displace Ag+ from AgNO₃. The deposit so obtained is black, soft, non-adhering.

To get a good shining deposit, [Ag (CN)₂]^– are used as it is a stable complex, the conc. of Ag⁺ is very small in the solution. As such no displacement of Ag⁺ ions with Cu is possible.

Ligand is a neutral molecule or charged ion which can donate a lone pair of electron to the metal.

Cyanocoblamine.

dsp² square planer.

(ii) Assertion and reason both are true but reason is not the correct explanation of assertion.

FeSO₄ does not form any complex with (NH₄)₂SO₄. Instead, it forms a double salt FeSO₄.(NH₄)₂SO₄.6H₂O which dissociates completely into ions. CuSO₄ when mixed with NH₃ forms a complex [CU(NH₃)₄]SO₄ in which the complex ion [CU(NH₃)₄]²⁺ does not dissociate to give Cu²⁺ ion.

 Ligand which can ligate through two different atoms e.g. CN^- , SCN^-

Correct answer is

(c) 9

Option : (b) inner, dimagnetic

(1) Linkage isomerism : The phenomenon of isomerism in which the coordination compounds have same metal atom or ion and same ligand but bonded through different donor atoms or linkages is known as linkage isomerism.

(2) Linkage isomers : The coordination compounds having same metal atom or ion and ligand but bonded through different donor atoms or linkages are called linkage isomers.

For example : 

Nitro complex [CO(NH₃)₅NO₂]CI₂ = (Yellow) and nitrito complex [CO(NH₃)₅ONO]CI₂ (Red)

(1) Nitro group (NO₂^-) is an ambidentate ligand. NO₂^- group may link to central metal atom, through N or O.

(2) The two linkage isomers are,

[CI : → Ag ← : NO₂^-] and [CI : → Ag ← O-NO]^-

Choloronitroargentate(I) ion and Chloronitritoargentate(I) ion

Hybridization : d² sp³

Shape : Octahedral

Magnetic character : Diamagnetic.

Option : (b) cancer

Option : (d) 36

In [Co(C₂O₄)₃]^3- , the coordination number of cobalt is six.

(i) K₃[CO(C₂O₄)₃]
The central metal ion is CO
coordination number: 6
oxidation state: +3
d orbital occupation : t⁶_2g eg⁰

(ii) cis-[Cr(en)₂Cl₂]Cl
central metal: Cr
coordination number: 6
oxidation state:+3 .
d orbital occupation : t³_2g eg⁰

(iii) (NH₄)₂[COF₄]
central metal: Co 

oxidation state: +2 

coordination number: 4

d orbital occupation : eg⁴ t³_2g

(iv) [Mn(H₂O)₆]SO₄

Central metal: Mn
coordination number: 6
oxidation state: +2
d orbital occupancy: t³_2g eg²

[Ni(NH₃)₆] Cl₂ → [Ni(NH₃)₆]²⁺ + 2Cl^-

Three ions. [CO(NH₃)₆]²⁺,2Cl^-.

(b) [NiCl₄]^2-

The answer is (a) +2

IUPAC name is Cyclohexa-1,3,5-triene.

(1) Geometrical isomerism : The phenomenon of isomerism in the heteroleptic coordination compounds with the same molecular formula but different spatial arrangement of the ligands in the space around the central metal atom or ion is called geometrical isomerism.

(2) Geometrical isomers : The heteroleptic coordination compounds having same molecular formula but different geometrical isomerism due to different spatial arrangements of the ligands in the space around the central metal atom or ion are called geometrical isomers.

(1) Stereoisomerism : The phenomenon of isomerism in the coordination compounds arising due to different spatial positions of the ligands in the space around the central metal atom or ion is called stereoisomerism.

(2) Stereoisomers : The coordination compounds having same molecular formula but different stereoisomerism due to different spatial arrangements of the ligand groups in the space around the central metal atom or ion are called stereoisomers.

Stereo isomers have the same chemical formula and chemical bonds but they have different spatial arrangement. 

They are of two kinds :

A. Geometrical isomerism 

B. Optical isomerism 

• Find the oxidation state of central metal ion in the complex. 
• Write the valence shell electronic configuration of metal ion. 
• From the formula of the complex determine the number of ligands and find the number of metal ion orbitais required for bonding. 
• Find the orbitais of metal ion available for hybridisation and the type of hybridisation involved. 
• Represent the electronic configuration of metal ion after hybridisation. 
• Exhibit filling of hybrid orbitais after complex formation. 
• Determine the nunther of unpaired electrons and predict magnetic property of the complex. 
• Find whether the complex is low spin or high spin (applicable for octahedral complexes with d⁴ or d⁸ electronic configuration) 

Option : (a) CN^-

Ligand is an atom/ion/molecule which is capable of donating pair of electrons to the metal atom or ion .

E.g Cl^-

Solvate ate or Hydrate isomerism : The phenomenon of isomerism in the coordination compounds arising due to the exchange of solvent or H₂O molecules inside the coordination sphere and outer sphere of the complex is known as solvate or hydrate isomerism.

• [Cu(NH₃)₄] [PICI₄] and I Pt(NH₃)₄] [ICuCl₄]
• [Cr(NH₃)₆] [Cr(CN)₆] and [Cr(NH₃)₄(CN)₂] [Cr(NH₃)₂(CN)₄]
• [Cr(NH₃)₆] [Cr(SCN)₆] and [Cr(NH₃)₄(SCN)₂] [Cr(SCN)₄(NH₃)₂] 

Coordination compounds are compounds in which a central metal atom or ion is linked to a number of ions or neutral molecules by coordinate bonds or which contain complex ions. 

Examples- K₄[Fe(CN)₆]; [ Cu(NH₃)₄]SO₄; Ni(CO)₄ 

(ii) Assertion and reason both are true but reason is not the correct explanation of assertion.

Option : (a) d²sp³

(i) Secondary valence 4

(ii) Secondary valence 6

(iii) Secondary valence 6

(iv) Secondary valence 6

In first case, colour will change from blue to deep blue.

[Cu (H₂O)₄] ²⁺ + 4 NH₃ → [Cu (NH₃)₄] ²⁺ + 4H₂O

[Cu (NH₃)₄] ²⁺ = deep blue

While in second case, its colour will change to yellow.

[Cu (H₂O)₄] ²⁺ + 4 Cl^– → [CuCl₄] ^2- + 4H₂O

[CuCl₄]^2- = Yellow

β₄ = 2.1×10¹³

The overall complex dissociation equilibrium constant is the reciprocal of the overall stability constant,β₄.

1/β₄ = 1/ 2.1×10¹³

= 4.7×10^-14 

It is because when NH₃ coordinates to Cu² ions it forms the complex [Cu(NH₃)₄]SO₄. Copper ions are present in coordination sphere, therefore, they are non- ionisable whereas SO₄ ^2- ions are counter ions which are ionisable.

Stability constant of [Ag(CN)₂]^2- is larger than that of [Ag(NH₃)₂]⁺ and hence [Ag(CN)₂]^2- is more stable. Also, CN is a stronger ligand than NH₃.

Option : (a) sp³, dsp², sp³

Hydration isomerism

Option : (d) d²sp³

Coordination compound : It consists of a central metal ion or atom surrounded by atoms, molecules or anions called ligands by coordinate bonds, e.g. cisplatin Pt(NH3)₂Cl₂, [Cu(NH₃)₄]SO₄.

Coordination sphere : A coordination entity consisting of a central metal atom or ion and the coordinating groups like neutral molecules or anions (ligands) written inside a square bracket is together called coordination sphere. This is a discrete structural unit. The ionisable groups (generally ions) called counter ions are written outside the bracket.

For example, in the coordination compound K₄ [Fe(CN)₆], the coordination sphere is [Fe(CN)₆]^4- while K⁺ represents counter ion.

• Lewis bases : In a coordination compound the ligands being electron pair donors they are Lewis bases. 
• Lewis acids : The central metal atom or ion being electron acceptor behaves as a Lewis acid. 
• For example, in the coordination compound, [Cu(NH₃)₄]²⁺, NH₃ is a Lewis base and Cu²⁺ is a Lewis acid. 

Lewis acid : Pt²⁺ 

Lewis bases : Cl^- and NF₃

[Co(H₂O)₄Cl₂]Cl (tetraaquadichloridocobalt(III) chloride)

(i), (iii)

(i) [Co(NH₃)₅ (NO₂)]²⁺  

(iii) [Cr(NH₃)₅ SCN]²⁺