Question
The wavelength of light absorbed for the following complexes are in the order \( (I) [ Co ( NH _3 )_6 ]^ 3+ ; (II) [ Co ( H _2 O )_6 ]^ 3+ ; (III) [ Co ( CN )_6 ]^ 3- ; (IV) [ Co ( NH _3 )_5 ( H _2 O ) ]^ 3+ ; (V) [ CoF _6 ]^ 3- \)
JEE Main
Chemistry
Coordination Compounds
2026
JEE Main 2026 (24 January Shift 2)
JEE Main Chemistry Question (2026) — Solution
Options
- A. III < I < IV < V < II
- B. III < I < IV < II < V
- C. III < I < II < IV < V
- D. III < IV < I < II < V
Answer
B. III < I < IV < II < V
Step-by-step solution
Wavelength of light absorbed increases as C.F.S.E of complex decreases. [Co(CN)_6]^ 3- has maximum CFSE [CoF_6]^ 3- has least CFSE Ligand field strength ; C.F.S.E Correct wavelength order. V > II > IV > I > III
Related: Chemistry — Coordination Compounds · All PYQ Banks