Question

Complex X of composition Cr(H₂O)₆Cln has a spin only magnetic moment of 3.83 BM. It reacts with AgNO₃ and shows geometrical isomerism. The IUPAC nomenclature of X is : 

(1) Tetraaquadichlorido chromium (III) chloride dihydrate 

(2) Hexaaqua chromium (III) chloride 

(3) Dichloridotetraaqua chromium (IV) chloride dihydrate 

(4) Tetraaquadichlorido chromium(IV) chloride dihydrate

Answer 1

Answer is (1)

Cr(H₂O)₆ Cln if magnetic mement is 3.83 BM then it contain three unpaired electrons. It means chromium in +3 oxidation state so molecular formula is Cr(H₂O)₆ Cl₃ 

∴ This formula have following isomers 

(a) [Cr(H₂O)₆]Cl₃ : react with AgNO₃ but does not show geometrical isomerism. 

(b) [Cr(H₂O)₅Cl]Cl₂.H₂O react with AgNO₃ but does not show geometrical isomerism. 

(c) [Cr(H₂O)₄Cl₂]Cl.2H₂O react with AgNO₃ & show geometrical isomerism. 

(d) [Cr(H₂O)₃Cl₃].3H₂O does not react with AgNO₃ & show geometrical isomerism. 

[Cr(H₂O)₄Cl₂]Cl.2H₂O react with AgNO₃ & show geometrical isomerism and it's IUPAC nomenclature is Tetraaquadichlorido chromium (III) Chloride dihydrate.

Answer 2

Answer is (1)