In the complex, potassium pentacyanonitrosylvandate (0), the number of potassium atoms per molecule and the coordination number of central metal ion are respectively

Options

A. 5,5
B. 4,6
C. 5,6
D. 4,4

Answer

To solve the problem regarding the complex potassium pentacyanonitrosylvanadate (0), we need to determine two things: the number of potassium atoms per molecule and the coordination number of the central metal ion (vanadium in this case).

### Step-by-Step Solution:

1. **Identify the Components of the Complex:**
The complex is potassium pentacyanonitrosylvanadate (0). Here, "pentacyano" indicates that there are five cyanide (CN) ligands, and "nitrosyl" indicates the presence of one nitrosyl (NO) ligand. The central metal ion is vanadium (V).

2. **Determine the Oxidation State of Vanadium:**
The overall charge of the complex is given as 0. The cyanide ion (CN) has a charge of -1, and since there are five of them, their total contribution to the charge is -5. The nitrosyl (NO) ligand is neutral in this case. Let the oxidation state of vanadium be \( x \). Therefore, we can set up the equation:
\[ x + (-5) + 0 = 0 \]
Simplifying this gives:
\[ x - 5 = 0 \implies x = +5 \]
Thus, the oxidation state of vanadium in this complex is +5.

3. **Count the Potassium Atoms:**
The potassium ions (K) are counter ions that balance the charge of the complex. Since the complex has a total charge of 0 and the vanadium is in the +5 oxidation state, we need 5 potassium ions (each K has a +1 charge) to balance the +5 charge from vanadium. Therefore, the number of potassium atoms per molecule is 5.

4. **Determine the Coordination Number of Vanadium:**
The coordination number is determined by the number of ligands directly bonded to the central metal ion. In this complex, there are five cyanide ligands and one nitrosyl ligand. Therefore, the total number of ligands is:
\[ 5 \, (\text{from } CN) + 1 \, (\text{from } NO) = 6 \]
Thus, the coordination number of the central metal ion (vanadium) is 6.

### Final Answer:
- The number of potassium atoms per molecule: **5**
- The coordination number of the central metal ion: **6**