Medium MCQ +4 / -1 PYQ · JEE Mains 2020

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. A Hexaaqua chromium (III) chloride
  2. B Tetraaquadichlorido chromium(IV) chloride dihydrate
  3. C Tetraaquadichlorido chromium (III) chloride dihydrate Correct answer
  4. D Dichloridotetraaqua chromium (IV) chloride dihydrate

Solution

Given complex Cr(H<sub>2</sub>O)<sub>6</sub>Cl<sub>n</sub> <br><br>As the magnetic mement is 3.83 BM then <br><br>Spin only magnetic moment = $\sqrt {n\left( {n + 2} \right)}$ BM = 3.83 <br><br>$\Rightarrow$ n = 3 <br><br>Chromium in +3 oxidation state so molecular formula is Cr(H<sub>2</sub>O)<sub>6</sub>Cl<sub>n</sub>. <br><br>$\therefore$ This formula have following isomers <br><br>(a) [Cr(H<sub>2</sub>O)<sub>6</sub>]Cl<sub>3</sub> : react with AgNO<sub>3</sub> but does not show geometrical isomerism. <br><br>(b) [Cr(H<sub>2</sub>O)<sub>5</sub>Cl]Cl<sub>2</sub>.H<sub>2</sub>O react with AgNO<sub>3</sub> but does not show geometrical isomerism. <br><br>(c) [Cr(H<sub>2</sub>O)<sub>4</sub>Cl<sub>2</sub>]Cl.2H<sub>2</sub>O react with AgNO<sub>3</sub> &amp; show geometrical isomerism. <br><br>(d) [Cr(H<sub>2</sub>O)<sub>3</sub>Cl<sub>3</sub>].3H<sub>2</sub>O does not react with AgNO<sub>3</sub> &amp; show geometrical isomerism. <br><br>Compound will be [Cr(H<sub>2</sub>O)<sub>4</sub>Cl<sub>2</sub>] Cl.2H<sub>2</sub>O <br><br>IUPAC NAME : Tetraaquadichlorido chromium(III) chloride dihydrate

About this question

Subject: Chemistry · Chapter: Coordination Compounds · Topic: Ligands and Coordination Number

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