JEE Main 2026 · 2 Apr · Shift 2 · Chemistry Q61

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ChemistrySingle correct+4 / -1Question 61 of 75

Which of the following complexes will show coordination isomerism ?

A. $\ce{[Ag(NH3)2][Ag(CN)2]}$

B. $\ce{[Co(NH3)6][Cr(CN)6]}$

C. $\ce{[Co(NH3)6][Co(CN)6]}$

D. $\ce{[Fe(NH3)6][Co(CN)6]}$

E. $\ce{[Co(NH3)6][Fe(CN)6]}$

Choose the correct answer from the options given below :

B, C and D Only

B, D and E Only

A, C and D Only

C, D and E Only

Answer and worked solution

Official answer: B

Coordination isomerism (NCERT) is the interchange of ligands between the cationic and anionic complexes of different metal ions, e.g. $\ce{[Co(NH3)6][Cr(CN)6]}$ and $\ce{[Cr(NH3)6][Co(CN)6]}$ .

B: Co/Cr ✓
D: Fe/Co ✓
E: Co/Fe ✓
A and C have the same metal in both ions, so swapping gives no new pairing of metal and ligands in this sense.

(B)

Topics:Isomerism in complexes

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JEE Main 2026 · 2 Apr · Shift 2, Chemistry question 61