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STATEMENT-1: Co^(+2) form octahedral st...

STATEMENT-1: `Co^(+2)` form octahedral stable complex with excess KCN.
and
STATEMENT-2: `CN^(-)` is stronger ligand than `NH_(3)` .

A

Statement-1 is True , Statement-2 is True , Statement-2 is a correct explanation for Statement-1

B

Statement-1 is True , Statement-2 is True , Statement-2 is NOT a correct explanation for Statement-1

C

Statement-1 is True , Statement-2 is False

D

Statement-1 is False , Statement-2 is True

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question, we need to analyze both statements provided: ### Step 1: Analyze Statement 1 **Statement 1:** "Co^(+2) forms octahedral stable complex with excess KCN." 1. **Identify the oxidation state of cobalt:** Cobalt in Co^(+2) has lost two electrons. 2. **Determine the electronic configuration of Co^(+2):** The atomic number of cobalt is 27, so its electron configuration is: - Co: [Ar] 3d^7 4s^2 - Co^(+2): [Ar] 3d^7 (after losing 2 electrons from 4s) 3. **Consider the ligand involved:** KCN dissociates into K^+ and CN^-. The CN^- ion is a strong field ligand. 4. **Effect of strong field ligands:** Strong field ligands like CN^- cause pairing of electrons in the d-orbitals. For Co^(+2) with a 3d^7 configuration, pairing would occur, but this leads to a situation where cobalt would prefer to lose an electron and get oxidized to Co^(+3) rather than forming a stable octahedral complex. 5. **Conclusion for Statement 1:** Cobalt(II) does not form a stable octahedral complex with CN^- due to its tendency to get oxidized to cobalt(III). Therefore, Statement 1 is **false**. ### Step 2: Analyze Statement 2 **Statement 2:** "CN^(-) is stronger ligand than NH3." 1. **Refer to the spectrochemical series:** The spectrochemical series ranks ligands based on their field strength. 2. **Position of CN^- and NH3:** In the spectrochemical series, CN^- is positioned above NH3, indicating that CN^- is a stronger field ligand compared to NH3. 3. **Conclusion for Statement 2:** Since CN^- is indeed a stronger ligand than NH3, Statement 2 is **true**. ### Final Conclusion - **Statement 1:** False - **Statement 2:** True Thus, the correct answer is **Option D:** Statement 1 is false, Statement 2 is true.
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