Question

Choose the complex which is paramagnetic:

• A. \( [\text{Fe} (\text{H}_2\text{O})_6]^{2+} \)
• B. \( K_3 [\text{Cr(CN)}_6] \)
• C. \( K_3 [\text{Fe(CN)}_6] \)
• D. \( K_2 [\text{Ni(CN)}_4] \)

Hint:

Paramagnetic complexes have unpaired electrons, which interact with an external magnetic field.

Answer 1

The Correct Option is A

A paramagnetic complex has unpaired electrons. \( [\text{Fe} (\text{H}_2\text{O})_6]^{2+} \) has unpaired electrons in the d-orbital, making it paramagnetic.
Final Answer: \[ \boxed{[\text{Fe} (\text{H}_2\text{O})_6]^{2+}} \]