Q. Which of the following complex compounds will exhibit highest paramagnetic behaviour? (At. No. Ti = 22, Cr = 24, Co = 27, Zn = 30)
A) [Co(NH₃)₆]³⁺
B) [Zn(NH₃)₆]²⁺
C) [Ti(NH₃)₆]³⁺
D) [Cr(NH₃)₆]³⁺
Explanation
[Solution from source] Cr³⁺ is d³ with 3 unpaired electrons in octahedral complexes. Co³⁺ (d⁶) with NH₃ is low spin with no unpaired electrons, Zn²⁺ is d¹⁰ with none, and Ti³⁺ is d¹ with one. So [Cr(NH₃)₆]³⁺ is the most paramagnetic. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.