Read the passage given below and answer the following questions :
According to Valence Bond Theory, the metal atom or ion under the influence of ligands can use its (n-1)d, ns, np or ns, np, nd orbitals for hybridisation to yield a set of equivalent orbitals of definite geometry such as octahedral, tetrahedral, square planar and so on. These hybridised orbitals ar allowed to overlap with ligand rbitals that can donate electron pairs for bonding.
Assertion (A) : `[NiCl_(4)]^(2-)` is an inner orbital complex.
Reason (R) : An inner orbital or low spin or spin paired complex uses inner d orbitals of the metal ion for hybridisation.

Options

A. Assertion and reason both are correct statements and reason is correct explanation for assertion.
B. Assertion and reason both are correct statements and reason is not correct explanation for assertion.
C. Assertion is correct statement but reason is wrong statement
D. Assertion is wrong statements but reason is correct statement.

Explanation

To solve the assertion and reason question regarding the complex \([NiCl_4]^{2-}\), we need to analyze both the assertion (A) and the reason (R) based on the principles of Valence Bond Theory and the nature of the ligands involved.

### Step-by-Step Solution:

**Step 1: Analyze the Assertion (A)**
- The assertion states that \([NiCl_4]^{2-}\) is an inner orbital complex.
- To determine if this is true, we need to consider the hybridization of nickel in this complex. Nickel (Ni) has an atomic number of 28, which means its electron configuration is \([Ar] 3d^8 4s^2\).
- In \([NiCl_4]^{2-}\), nickel is in the +2 oxidation state, leading to the configuration of \(3d^8\).
- The ligand \(Cl^-\) is a weak field ligand. Weak field ligands do not cause pairing of electrons in the \(d\) orbitals.
- Therefore, nickel will use its \(4s\) and \(4p\) orbitals along with the \(3d\) orbitals for hybridization, leading to \(sp^3\) hybridization.
- This indicates that \([NiCl_4]^{2-}\) is actually an outer orbital complex (OOC), not an inner orbital complex (IOC).

**Conclusion for Assertion (A):** The assertion is **false**.

**Step 2: Analyze the Reason (R)**
- The reason states that an inner orbital or low spin or spin paired complex uses inner \(d\) orbitals of the metal ion for hybridization.
- This statement is generally true. Inner orbital complexes (like those formed with strong field ligands) utilize the \(n-1d\) orbitals for hybridization, resulting in low spin configurations due to electron pairing.
- Since the reason correctly describes the characteristics of inner orbital complexes, this statement is **true**.

**Conclusion for Reason (R):** The reason is **true**.

**Final Conclusion:**
- Assertion (A) is false, and Reason (R) is true. Therefore, the correct answer is that the assertion is incorrect while the reason is correct.

### Answer:
The correct option is **4**: Assertion is false, Reason is true.

---