Which of the following statement is correct ?

Options

A. The oxidation state of iron in sodium nitro prusside `Na_(2)[Fe(CN)_(5)(NO))[` is +3
B. `[Ag(NH_(3))_(2)]^(+)` is linear in shape
C. In `[Fe(H_(2)O)_(6)]^(3+)`, Fe is `d^(2)sp^(3)` hybridized
D. In `Ni(CO)_(4)`, the oxidation state of Ni is 1

Answer

To solve the question regarding which statement is correct, we will analyze each statement one by one.

### Step 1: Analyze the first statement regarding Na2Fe(CN)5NO
- The complex is Na2Fe(CN)5NO.
- The overall charge of the complex is -2 (due to Na2).
- Let the oxidation state of iron (Fe) be \(X\).
- Each cyanide (CN) has an oxidation state of -1, and there are 5 cyanides, contributing -5.
- The nitrosyl (NO) has an oxidation state of +1.
- Setting up the equation for the charge balance:
\[ X - 5 + 1 = -2 \]
Simplifying gives:
\[ X - 4 = -2 \implies X = +2 \]
- Therefore, the oxidation state of iron in this complex is +2, not +3. This statement is **incorrect**.

### Step 2: Analyze the second statement regarding Ag(NH3)2^+
- The complex is Ag(NH3)2^+.
- Ammonia (NH3) is a neutral ligand and coordinates to silver (Ag) through lone pair donation.
- The geometry of this complex is linear because it involves two ligands arranged around the central metal atom.
- Therefore, this statement is **correct**.

### Step 3: Analyze the third statement regarding [Fe(H2O)6]^(3+)
- The complex is [Fe(H2O)6]^(3+).
- Water (H2O) is a weak field ligand, which means it does not cause pairing of electrons.
- For Fe^(3+), the electronic configuration is [Ar] 3d^5.
- Since water does not cause pairing, the hybridization is sp^3d^2, not d^2sp^3.
- Therefore, this statement is **incorrect**.

### Step 4: Analyze the fourth statement regarding Ni(CO)4
- The complex is Ni(CO)4.
- Carbon monoxide (CO) is a neutral ligand.
- Therefore, the oxidation state of nickel (Ni) in this complex is 0.
- The statement claiming the oxidation state of nickel is +1 is **incorrect**.

### Conclusion
The only correct statement among the options provided is the second one regarding Ag(NH3)2^+, which is linear in shape.

### Final Answer
The correct statement is: **Ag(NH3)2^+ is linear in shape.**

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