Which of the following primary and secondary valencies are not correctly marked against the compound ?

Options

A. `[Cr(NH_(3))_(6)]Cl_(3) , p = 3 , s = 6`
B. `K_(2) [PtCl_(4)] , p = 2 , s = 4`
C. `[Pt(NH_(3))_(2) Cl_(2)], p = 2 , s = 4 `
D. `[Cu(NH_(3))_(4)]SO_(4), p = 2 , s = 4 `

Explanation

To solve the question regarding the primary and secondary valencies of the given coordination compounds, we will analyze each compound step by step.

### Step-by-Step Solution:

1. **Understanding Primary and Secondary Valencies**:
- **Primary Valency**: This refers to the total charge of the complex, which is satisfied by the anions and cations present in the compound.
- **Secondary Valency**: This is related to the coordination number, which is the number of ligands directly bonded to the central metal atom.

2. **Analyzing Each Compound**:
- **Compound 1: [Cr(H2O)6]Cl3**
- **Cation**: Cr^3+ (Chromium ion)
- **Anions**: 3 Cl^- (Chloride ions)
- **Primary Valency**: 3 (from 3 Cl^-)
- **Coordination Number**: 6 (from 6 H2O ligands)
- **Secondary Valency**: 6
- **Conclusion**: Both primary (3) and secondary (6) valencies are correctly marked.

- **Compound 2: [Co(NH3)2Cl2]**
- **Cation**: Co^2+ (Cobalt ion)
- **Anions**: 2 Cl^- (Chloride ions)
- **Primary Valency**: 2 (from 2 Cl^-)
- **Coordination Number**: 4 (2 NH3 and 2 Cl)
- **Secondary Valency**: 4
- **Conclusion**: Both primary (2) and secondary (4) valencies are correctly marked.

- **Compound 3: [Pt(NH3)2Cl2]**
- **Cation**: Pt^2+ (Platinum ion)
- **Anions**: 2 Cl^- (Chloride ions)
- **Primary Valency**: 2 (from 2 Cl^-)
- **Coordination Number**: 4 (2 NH3 and 2 Cl)
- **Secondary Valency**: 4
- **Conclusion**: Here, the primary valency is often considered as 0 because there are no anions that balance the charge of the metal ion. If the primary valency is incorrectly marked as 2, then this is incorrect.

- **Compound 4: [Cu(NH3)4]SO4**
- **Cation**: Cu^2+ (Copper ion)
- **Anion**: SO4^2- (Sulfate ion)
- **Primary Valency**: 2 (from SO4^2-)
- **Coordination Number**: 4 (from 4 NH3 ligands)
- **Secondary Valency**: 4
- **Conclusion**: Both primary (2) and secondary (4) valencies are correctly marked.

3. **Final Conclusion**:
- The primary and secondary valencies that are not correctly marked are for **Compound 3: [Pt(NH3)2Cl2]**, where the primary valency is incorrectly marked as 2 instead of 0.

### Summary of Incorrect Markings:
- **Incorrectly marked**: Compound 3: [Pt(NH3)2Cl2] (Primary valency should be 0, not 2).