University of Delhi 2008 B.Sc Chemistry inorganic - xiii - Question Paper

Q1. (a) provide the name of the subsequent complexes according to IUPAC nomenclature

i. [Ag(NH3)2] [Ag(CN)2]
ii. [NiBr2(PEt3)2]
iii. [(Cl3Sn)2RhCl2Rh(SnCl3)2]4-

(b) Write the formulae of the subsequent :

i. Tetramethylammonium hexathiocyanato-N-Chromate(III)

ii. µ-imido-µ-superoxobis(tetraamminecobalt-(III))chloride

iii. Aluminium tetrachloroplatinate(II)


(c) A four coordinated complex [MA2B2] exists in two isomeric forms I & II. I has a dipole moment of 6.0D units and II 20.1D. Draw the structures of I and II.

Q2. (a) The magnetic moment of [Fe(H2o)6]3+ was obtained to be 4.9BM and of [Fe(CN)6]3- to be 1.9T BM. Account for the above observation on the basis of valence bond theory.

(b) Indicate the kind of isomerism exhibited by the subsequent pairs of isomers and suggest 1 tests in every set to distinguish them.

i. [Cr(NH3)6] [Co(NO2)6] and [Co(NH3)6] [Cr(NO2)6]

ii. [Co(H2O)5Cl]Cl2.H2O and [Co(H2O)4Cl2]Cl.2H2O


(c) Which complex in every of the subsequent pairs will have greater crystal field splitting and why ?

i. [Co(NH3)6]3+ and[Rh(NH3)6]3+

ii. [Co(NO2)6]3- and [Co(O

Q3. For the complex [Cr(H2O)6]2+ the mean pairing energy P=23500 cm-1 and magnitude of ?o =13900cm-1

(a) Calculate CFSE of the complex corresponding to high spin and low spin arrangements.

(b) Will the complex exist in high or low spin arrangement.

(c) The arrangement you have chosen (i) will the complex be labile or inert (ii) will it have a regular geometry or distorted geometry. Justify your ans.

(d) What kind of complex (HS/LS) will be found when 10Dq=P.


Q4. (a) The Latimer diagram for manganese in acidic and alkaline medium are provided beneath.

Acidic MnO4- ------- MnO42- --------MnO2 ------Mn3+ -------Mn2+------Mn
Medium +0.56 +2.26 +0.95 +1.51 -1.19


Alkaline MnO4- ------MnO42- ------MnO43- -------MnO2 ------ MN3+ -----Mn(?t)2
Medium +0.56 +0.27 +0.93 +0.1 -0.2

-1.55

Mn

i. In which medium MnO2 will act as oxidizing agent and why ?

ii. Which states will undergo disproportionation in acidic medium and why ?


(b) With the help of molecular orbital theory discuss the position of CO as a strong field ligand in spectrochemical series.

(c) discuss why ligands like CO tend to form complexes with metals in low oxidation states.


Q5. (a) discuss whether NiFe2O4 will adopt a normal spinel structure or inverse spinel structure.

(b) Why is the lone absorption band in the visible spectrum of [Ti(H2O)6]3+ is a few what broad and unsymmetrical.

(c) The experimentally determined hydration energy for Mn2+ agrees with the computed value. But for Fe2+ and Co2+ the experimentally determined value is obtained to be higher than the computed value.

Q6. (a) How would you prepare cis and trans isomers of [PtCl2(NO2)NH3] using [PtCl4]2-, NH3 and NO2-. discuss the procedure you have adopted.

(b) The stepwise formation of [Fe(H2O)6]2+ to [Fe(Phen)3]2+ is provided beneath.
[Fe(H2O)6]2+ + Phen ? [Fe(H2O)4Phen]22+ + Phen ? [Fe(H2O)2(phen)2]2+ + Phen
k1 k2
k3

[Fe(Phen)3]2+ ?

discuss why i. k1>k2

ii. k3>k2

iii. Choose the complex which will be inert and justify your option.

(c) The 2 water molecules in [Cu(H2O)6]2+ ion undergo exchange with large excess of solvent molecules much more rapidly than the other four. discuss


Q7. (a) An orange coloured compound A on treatment with Conc. HCl provide a yellow gas and a green coloured compound B. B on treatment with Zinc in the presence of dil. HCl gave a blue coloured. Compound C. C on treatment with sodium acetate gave a red compound D. giving balanced chemical formula identify A, B ,C and D. explain the structure and magnetic property of D

(b) discuss the amphoteric nature of V2O5.


Q8. (a) What is lanthanide contraction? provide any 2 consequences of it.

(b) Account for the subsequent :

i. Transition metals and their compounds act as good catalysts.

ii. Actinides have a greater tendency to form complexes than lanthanides.


(c) Why 4d and 5d elements usually form low spin complexes?

Earning:   Approval pending.