Question
The correct order of the wavelength maxima of the absorption band in the ultraviolet-visible region for the given complexes is
JEE Advanced
Chemistry
Coordination Compounds
2025
JEE Advanced 2025 (Paper 1)
JEE Advanced Chemistry Question (2025) — Solution
Options
- A. [ Co ( CN )_6 ]^ 3- < [ Co ( NH _3 )_6 ]^ 3+ < [ Co ( NH _3 )_5 ( H _2 O ) ]^ 3+ < [ Co ( NH _3 )_5( Cl ) ]^ 2+
- B. [ Co ( NH _3 )_5( Cl ) ]^ 2+ < [ Co ( NH _3 )_5 ( H _2 O ) ]^ 3+ < [ Co ( NH _3 )_6 ]^ 3+ < [ Co ( CN )_6 ]^ 3-
- C. [ Co ( CN )_6 ]^ 3- < [ Co ( NH _3 )_5( Cl ) ]^ 2+ < [ Co ( NH _3 )_5 ( H _2 O ) ]^ 3+ < [ Co ( NH _3 )_6 ]^ 3+
- D. [ Co ( NH _3 )_6 ]^ 3+ < [ Co ( CN )_6 ]^ 3- < [ Co ( NH _3 )_5( Cl ) ]^ 2+ < [ Co ( NH _3 )_5 ( H _2 O ) ]^ 3+
Answer
A. [ Co ( CN )_6 ]^ 3- < [ Co ( NH _3 )_6 ]^ 3+ < [ Co ( NH _3 )_5 ( H _2 O ) ]^ 3+ < [ Co ( NH _3 )_5( Cl ) ]^ 2+
Step-by-step solution
_ O 1 aligned & The absorb wave length order is \\ & [ Co ( CN )_6 ]^ 3- < [ Co ( NH _3 )_6 ]^ 3+ < [ Co ( NH _3 )_5 H _2 O ]^ 3+ < [ Co ( NH _3 )_5 Cl ]^ 2+ aligned
Related: Chemistry — Coordination Compounds · All PYQ Banks