What kind of isomerism exists between `[Cr(H_(2)O)_(6)]Cl_(3)` (violet) and `[Cr(H_(2)O)_(5)Cl].H_(2)O` (greyish-green)?

Options

A. Linkage isomersim
B. Solvate isomerism
C. Ionisation isomerism
D. Coordination isomerism

Explanation

To determine the type of isomerism that exists between the complexes \([Cr(H_2O)_6]Cl_3\) (violet) and \([Cr(H_2O)_5Cl] \cdot H_2O\) (greyish-green), we can follow these steps:

### Step 1: Identify the coordination complexes
- The first complex is \([Cr(H_2O)_6]Cl_3\), which indicates that chromium is coordinated to six water molecules and is associated with three chloride ions outside the coordination sphere.
- The second complex is \([Cr(H_2O)_5Cl] \cdot H_2O\), which shows that chromium is coordinated to five water molecules and one chloride ion, with an additional water molecule outside the coordination sphere.

### Step 2: Analyze the number of ions
- In \([Cr(H_2O)_6]Cl_3\), the total number of ions when dissolved in solution is four: one \([Cr(H_2O)_6]^{3+}\) ion and three \(Cl^-\) ions.
- In \([Cr(H_2O)_5Cl] \cdot H_2O\), the total number of ions is three: one \([Cr(H_2O)_5Cl]^{2+}\) ion and one \(H_2O\) molecule that does not dissociate into ions.

### Step 3: Determine the type of isomerism
- Since the two complexes have different numbers of ions in solution, they exhibit ionization isomerism. Ionization isomerism occurs when two or more coordination compounds have the same formula but differ in the ions that are released into the solution.
- Additionally, the second complex can also be classified as a solvate isomer because it contains a water molecule that is not coordinated to the metal ion but is instead present as a solvent molecule.

### Conclusion
The type of isomerism that exists between \([Cr(H_2O)_6]Cl_3\) and \([Cr(H_2O)_5Cl] \cdot H_2O\) is **ionization isomerism** and **solvate isomerism**.

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