Medium MCQ +4 / -1 PYQ · JEE Mains 2021

Arrange the following Cobalt complexes in the order of increasing Crystal Field Stabilization Energy (CFSE) value.

Complexes : $$\mathop {{{[Co{F_6}]}^{3 - }}}\limits_A ,\mathop {{{[Co{{({H_2}O)}_6}]}^{2 + }}}\limits_B ,\mathop {{{[Co{{(N{H_3})}_6}]}^{3 + }}}\limits_C and \mathop {{{[Co{{({en})}_3}]}^{3 + }}}\limits_D $$

Choose the correct option :

  1. A A < B < C < D
  2. B B < A < C < D Correct answer
  3. C B < C < D < A
  4. D C < D < B < A

Solution

(i) CFSE $\propto$ charge or oxidation no. of central metal ion.<br><br>(ii) CFSE $\propto$ strength of ligand<br><br>en &gt; NH<sub>3</sub> &gt; H<sub>2</sub>O &gt; F<sup>$-$</sup><br><br>$\therefore$ order of CFSE<br><br>$$\mathop {{{[Co{{(en)}_3}]}^{ + 3}}}\limits^{III} &gt; \mathop {{{[Co{{(N{H_3})}_6}]}^{ + 3}}}\limits^{III} &gt; \mathop {{{[Co{F_6}]}^{ - 3}}}\limits^{III} &gt; \mathop {{{[Co{{({H_2}O)}_6}]}^{ + 2}}}\limits^{III} $$

About this question

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

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