Question

The correct order for wavelengths of light absorbed in the complex ions ${\left[CoCl{\left(N{H}_3\right)}_5\right]}^{2+},{\left[Co{\left(N{H}_3\right)}_6\right]}^{3+}$ and ${\left[Co(CN{)}_6\right]}^{3-}$ is

• A. ${\left[CoCl{\left(N{H}_3\right)}_5\right]}^{2+}>{\left[Co{\left(N{H}_3\right)}_6\right]}^{3+}>{\left[Co(CN{)}_6\right]}^{3-}$
• B. ${\left[Co{\left(N{H}_3\right)}_6\right]}^{3+}>{\left[Co(CN{)}_6\right]}^{3-}>{\left[CoCl{\left(N{H}_3\right)}_5\right]}^{2+}$
• C. ${\left[Co(CN{)}_6\right]}^{3-}>{\left[CoCl{\left(N{H}_3\right)}_5\right]}^{2+}>{\left[Co(CN{)}_6\right]}^{3-}$
• D. ${\left[Co{\left(N{H}_3\right)}_6\right]}^{3+}>\left[CoCl{\left(N{H}_3\right)}_5\right]>{\left[Co(CN{)}_6\right]}^{3-}$

Answer 1

Answer: (A)

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