JEE Main · 2004 · 24 Apr 2004 · Offline · Coordination Compounds

Which one the following has largest number of isomers?
(R = alkyl group, en = ethylenediamine)

(A) $[Ru (NH_{3})_{4} Cl_{2}^{+}]$
(B) $[Co (en)_{2} Cl_{2}]^{+}$ ✓ Correct
(C) $[lr (PR_{3})_{2} H (CO)]^{2 +}$
(D) $[Co (NH_{3})_{5} Cl]^{2 +}$

Answer: (B)

Solution

Look for the complex that opens up both geometrical and optical isomerism.

[Co (en) X_{2} Cl X_{2}] X^{+}

is octahedral with two bidentate en ligands and two chlorides: it has cis and trans forms, and the cis form is itself chiral, splitting into a pair of enantiomers, so it musters three isomers in all. The ammine and mixed-ligand complexes offered manage fewer, so this one carries the largest number of isomers.

JEE Main · 2004 · 24 Apr 2004 · Offline · Single correct option

Practise more: all JEE Main PYQs on Coordination Compounds →

More JEE Main questions on Coordination Compounds

Given below are two statements:

Statement I: Among $[Cu (NH_{3})_{4}]^{2 +}$ , $[Ni (en)_{3}]^{2 +}$ , $[Ni (NH_{3})_{6}]^{2 +}$ and $[Mn (H_{2} O)_{6}]^{2 +}$ , …
JEE Main 2026View solution →
Consider the transition metal ions $Mn^{3 +}, Cr^{3 +}, Fe^{3 +}$ and $Co^{3 +}$ and all form low spin octahedral complexes. The correct decreasing order of unpaired electrons in their respective d-orbitals of the complexes is
JEE Main 2026View solution →
A first row transition metla (M) does not liberate $H_{2}$ gas from dilute HCl .1 mol of aqueous solution of $MSO_{4}$ is treated with excess of aqueous KCN and then $H_{2} S (g)$ is passed through the solution. The amount of MS …
JEE Main 2026View solution →
Given below are two statements:

Statement I: Crystal Field Stabilization Energy (CFSE) of $[Cr (H_{2} O)_{6}]^{2 +}$ is greater than that of $[Mn (H_{2} O)_{6}]^{2 +}$ .

Statement II: Pot …
JEE Main 2026View solution →
Identify the metal ions among $Co^{2 +}$ , $Ni^{2 +}$ , $Fe^{2 +}$ , $V^{3 +}$ and $Ti^{2 +}$ having a spin-only magnetic moment value more than 3.0 BM. The sum of unpaired electrons present in the high spin octahedral complexes formed by thos …
JEE Main 2026View solution →
$[Ni (PPh_{3})_{2} Cl_{2}]$ is a paramagnetic complex. Identify the INCORRECT statements about this complex.
A. The complex exhibits geometrical isomerism.
B. The complex is white in colour.
C. The calculated spin-only magnetic moment of the complex is 2. …
JEE Main 2026View solution →