KCET2021ChemistryCoordination Compounds
The correct order for wavelengths of light absorbed in the complex ions [ CoCl ( NH ₃ )₅ ]²⁺, [ Co ( NH ₃ )₆ ]³⁺ and [ Co ( CN )₆ ]³⁻ is
Options
- A[ CoCl ( NH ₃ )₅ ]²⁺> [ Co ( NH ₃ )₆ ]³⁺> [ Co ( CN )₆ ]³⁻
- B[ Co ( NH ₃ )₆ ]³⁺> [ Co ( CN )₆ ]³⁻> [ CoCl ( NH ₃ )₅ ]²⁺
- C[ Co ( CN )₆ ]³⁻> [ CoCl ( NH ₃ )₅ ]²⁺> [ Co ( CN )₆ ]³⁻
- D[ Co ( NH ₃ )₆ ]³⁺> [ CoCl ( NH ₃ )₅ ]²⁺> [ Co ( CN )₆ ]³⁻
Correct answer
A. [ CoCl ( NH ₃ )₅ ]²⁺> [ Co ( NH ₃ )₆ ]³⁺> [ Co ( CN )₆ ]³⁻
Step-by-step solution
Wavelengths of light absorbed is inversely proportional to strength of the ligand and order of strength of the given ligand is CN ⁻> NH ₃> Cl ⁻ . Therefore, the correct order for wavelength of light absorbed in the complex ions is [ CoCl ( NH ₃ )₅ ]²⁺> [ Co ( NH ₃ )₆ ]³⁺> [ Co ( CN )₆ ]³⁻