| List-I Coordination entity | List-II Wavelength of light absorbed in nm | ||
| A. | \([CoCl(NH_3)_5]^{2+}\) | I. | 310 |
| B. | \([Co(NH_3)_6]^{3+}\) | II. | 475 |
| C. | \([Co(CN)_6]^{3−}\) | III. | 535 |
| D. | \([Cu(H_2O)_4]^{2+}\) | IV. | 600 |
The correct answer is (A) : A-III, B-II, C-I, D-IV
| LIST I Coordination entity | LIST II Wavelength of light absorbed in nm | ||
|---|---|---|---|
| A | \([CoCl(NH_3)_5]^{2+}\) | I | 535 |
| B | \([Co(NH_3)_6]^{3+}\) | II | 475 |
| C | \([Co(CN)_6]^{3−}\) | III | 310 |
| D | \([Cu(H_2O)_4]^{2+}\) | IV | 600 |
\(E=\frac{hc}{λ}⇒E∝\frac{1}{λ}\)
\(⇒Δ(CFSE)∝\frac{1}{λ_{absorb}} 1∝ \)strength of ligand.

Consider the following sequence of reactions : 
Molar mass of the product formed (A) is ______ g mol\(^{-1}\).
A coordination compound holds a central metal atom or ion surrounded by various oppositely charged ions or neutral molecules. These molecules or ions are re-bonded to the metal atom or ion by a coordinate bond.
A coordination entity composes of a central metal atom or ion bonded to a fixed number of ions or molecules.
A molecule, ion, or group which is bonded to the metal atom or ion in a complex or coordination compound by a coordinate bond is commonly called a ligand. It may be either neutral, positively, or negatively charged.