Select incorrect statement about complex `[Cr(NO_(2))(NH_(3))_(5)][Zn(SCN)_(4)]:`

Options

A. It shows co-ordination isomersm
B. it shows optical activity
C. It shows linkage isomerism
D. IUPAC name of the compound is pentaaminenitrito-N-chromium(III) tetrathiocyanato-S-zincate(II)

Explanation

To determine the incorrect statement about the complex \([Cr(NO_2)(NH_3)_5][Zn(SCN)_4]\), we will analyze each statement related to the complex and identify which one is false.

### Step-by-Step Solution:

1. **Understanding the Complex**:
The given complex is a coordination compound consisting of a cation \([Cr(NO_2)(NH_3)_5]^{2+}\) and an anion \([Zn(SCN)_4]^{2-}\).

2. **Identifying Coordination Isomerism**:
- Coordination isomerism occurs when the ligands can be interchanged between the metal centers.
- In this complex, since there are two different metal centers (Cr and Zn), it can exhibit coordination isomerism.
- **Conclusion**: This statement is **true**.

3. **Checking for Optical Activity**:
- A complex is optically active if it has a non-superimposable mirror image (chiral).
- In the case of \([Cr(NO_2)(NH_3)_5]^{2+}\), both the nitro and ammonia ligands are monodentate and symmetrical, meaning that any arrangement will have a superimposable mirror image.
- Similarly, the anion \([Zn(SCN)_4]^{2-}\) is also symmetrical and does not have a chiral center.
- **Conclusion**: This statement is **false**.

4. **Linkage Isomerism**:
- Linkage isomerism occurs when a ligand can coordinate to the metal in more than one way.
- The thiocyanate ion (SCN) can bind through sulfur (thiocyanate) or nitrogen (isothiocyanate), allowing for linkage isomerism.
- **Conclusion**: This statement is **true**.

5. **IUPAC Naming and Oxidation States**:
- The IUPAC name for the complex is correctly identified as pentamine nitrate(II) chromium(III) tetra-thiocyanato zinc(II).
- The oxidation state of chromium can be calculated as follows:
- Let the oxidation state of Cr be \(x\).
- The charges from the ligands: \(5 \times 0 + (-1) + x = +2\) gives \(x = +3\).
- The oxidation state of Zn in \([Zn(SCN)_4]^{2-}\) can also be calculated similarly, confirming it as \(+2\).
- **Conclusion**: This statement is **true**.

### Summary of Findings:
- The incorrect statement about the complex \([Cr(NO_2)(NH_3)_5][Zn(SCN)_4]\) is that it shows optical activity.