On the basis of crystal field theory, explain why Mn H 2 O 6 2 + contains five unpaired electrons while Mn CN 6 4 - contains only one unpaired electron.

In [ Mn ( H 2 O ) 6 ] - 2 water is the weak field ligand. In [ Mn ( CN ) 6 ] - 4 cyanide is strong field ligand. Therefore, the arrangement of the electrons is T 2 g 5 e g 0 . Hence, hexaaquo manganese (ll) ion has five unpaired electrons, while hexacyano ion has only one unpaired electron.

With the help of a diagram, give the splitting of d -orbitals of Mn 2 + ion in an octahedral crystal field.

In octahedral symmetry the d-orbitals split into two sets with an energy difference, where the d xy , d yz , d zx orbitals will be lower in energy than the d z 2 , d x 2 - y 2 which will have higher energy, because the former group is farther from the ligands than the latter and therefore experience less repulsion. Electron configuration of Mn + 2 = 4 s 0 3 d 5 Splitting of d -orbitals of Mn 2 + ion in an octahedral crystal field: Case-1, Approaching of weak field ligands towards Mn + 2 ion (high spin complex) Case-2, Approaching of strong field ligands towards Mn + 2 ion (low spin complex)

Cis isomer of Pt NH 3 2 Cl 2 is used to inhibit the growth of tumours. Give the IUPAC name of Pt NH 3 2 Cl 2 .

Consider the complex Pt NH 3 2 Cl 2 , The central metal platinum is in + 2 oxidation state. There are two ammine ( NH 3 ) and two chlorido ( Cl - ) ligands are bonded to the platinum ion. According to IUPAC rules, this complex is named starting from the ligands in alphabetical order followed by the name of the metal with its oxidation state. Hence, the IUPAC name becomes, diamminedichloridoplatinum( II ).

Assign the primary valence and secondary valence of the central metal in Ni CO 4 .

The primary valency of metal is the oxidation state of the metal in the complex, and the secondary valency is the coordination number of the metal. In Ni CO 4 , carbonyl group ( CO ) is a neutral ligand, therefore, the oxidation state of nickel is zero, hence the primary valency is zero. There are four CO ligands attached to the central metal, therefore, the secondary valency of nickel is four.

Explain how the complexes of Ni , Ni CN 4 2 - and Ni CO 4 have different structures but do not differ in their magnetic behaviour ( Ni Atomic No : 28 ).

The complex [ Ni ( CN ) 4 ] 2 - is square planar and dsp 2 hybridisation occurs while [ Ni ( CO ) 4 ] is tetrahedral and sp 3 hybridisation occurs. The difference arises because of the oxidation states of the metal atom/ion in the two complexes and have different structures. But since all the electron orbitals of the central metal atom/ion in these complexes are paired, both are therefore, diamagnetic in nature and do not differ in their magnetic behaviour.

Write any two limitations of valance bond theory.

The limitations of valence bond theory are: It fails to explain the tetra valency of carbon. This theory does not discuss the electrons' energy. The theory assumes that electrons are localized in specific areas. It does not give a quantitative interpretation of the thermodynamic or kinetic stabilities of coordination compounds and there exists no distinction between weak and strong ligands.

Write the formula of pentaamminecarbonatocobalt (lll) chloride.

The formula of Pentaamminecarbonatocobalt(lll) chloride is given as [ Co ( NH 3 ) 5 ( CO 3 ) ] Cl - . Here, the oxidation state of Co is +3 and neutral ligand ammonia carries zero charge and carbonate ion and chloride ion carries -2,-1 charges respectively.

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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR CHEMISTRY>Chapter -1 - Coordination Compounds>Kerala Board-2020>Q 10

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Give the structure of cis and trans isomers of $[Pt {({NH}_{3})}_{2} {Cl}_{2}]$ .

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