AIIMS2007ChemistryCoordination Compounds
Wavelength of red light is absorbed by the complex
Options
- A( [ Cu ( CN )₄ ]²⁻ )
- B( [ Cu ( NH ₃ )₄ ]²⁺ )
- C( CuSO ₄ )
- D( Cu ( CN )₂ ).
Correct answer
B. ( [ Cu ( NH ₃ )₄ ]²⁺ )
Step-by-step solution
When ( NH ₄ OH ) is added to the solution containing ( Cu ²⁺ ) ions, deep blue solution is obtained. ( Cu ²⁺+4 NH ₄ OH deep blue solution [ Cu ( NH ₃ )₄ ]²⁺ +4 H ₂ O ) Hydrated cupric compounds absorb radiations corresponding to red light and the transmitted colour is greenish blue (which is complementary to red colour). Thus, cupric compounds give greenish-blue colour.