Question

The correct order for wavelengths of light absorbed in the complex ions $\left[ CoCl \left( NH _{3}\right)_{5}\right]^{2+},\left[ Co \left( NH _{3}\right)_{6}\right]^{3+}$ and $\left[ Co ( CN )_{6}\right]^{3-}$ is

• A. $\left[ CoCl \left( NH _{3}\right)_{5}\right]^{2+}>\left[ Co \left( NH _{3}\right)_{6}\right]^{3+}>\left[ Co ( CN )_{6}\right]^{3-}$
• B. $\left[ Co \left( NH _{3}\right)_{6}\right]^{3+}>\left[ Co ( CN )_{6}\right]^{3-}>\left[ CoCl \left( NH _{3}\right)_{5}\right]^{2+}$
• C. $\left[ Co ( CN )_{6}\right]^{3-}>\left[ CoCl \left( NH _{3}\right)_{5}\right]^{2+}>\left[ Co ( CN )_{6}\right]^{3-}$
• D. $\left[ Co \left( NH _{3}\right)_{6}\right]^{3+}>\left[ CoCl \left( NH _{3}\right)_{5}\right]>\left[ Co ( CN )_{6}\right]^{3-}$

Answer 1

Answer: (A)

Wavelength of light absorbed is inversely proportional to strength of the ligand.