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QJEEM20Ch4145: JEE Main 2020 Chemistry - Class 12 JEEM20Ch4145 Solution: Complex X of composition Cr(H 2 O) 6 Cl n has a spin only…

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 :

Multiple Choice Options

  • A Hexaaqua chromium (III) chloride
  • B Tetraaquadichlorido chromium(IV) chloride dihydrate
  • C Tetraaquadichlorido chromium (III) chloride dihydrate
  • D Dichloridotetraaqua chromium (IV) chloride dihydrate

Step-by-Step Verified Solution

Given complex Cr(H2O)6Cln

As the magnetic mement is 3.83 BM then

Spin only magnetic moment = n(n+2) BM = 3.83

⇒ n = 3

Chromium in +3 oxidation state so molecular formula is Cr(H2O)6Cln.

∴ 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.

Compound will be [Cr(H2O)4Cl2] Cl.2H2O

IUPAC NAME : Tetraaquadichlorido chromium(III) chloride dihydrate

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