A: `[Cr (H_(2)O)_(6)]^(3+)` is Inner orbital complex.
R: `H_(2)O` is strong ligand generally

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1)
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2).
C. ) If Assertion is true statement but Reason is false, then mark (3).
D. If both Assertion and Reason are false statements, then mark (4)

Answer

To solve the question regarding the assertion and reason about the complex `[Cr(H₂O)₆]³⁺`, we will break down the problem step by step.

### Step 1: Analyze the Assertion
The assertion states that `[Cr(H₂O)₆]³⁺` is an inner orbital complex.

- **Chromium (Cr)** has an atomic number of 24. Its electron configuration is:
- Ground state: [Ar] 4s² 3d⁵
- When chromium is in the +3 oxidation state, it loses three electrons:
- The two electrons from the 4s subshell and one from the 3d subshell, resulting in the configuration: [Ar] 3d³.

### Step 2: Determine the Hybridization
In an octahedral complex like `[Cr(H₂O)₆]³⁺`, the d-orbitals split into two sets: the lower-energy t₂g (3 orbitals) and the higher-energy e_g (2 orbitals).

- For the d³ configuration, the three electrons will occupy the lower-energy t₂g orbitals:
- This leads to the hybridization of the complex being d²sp³, where:
- d (3d) orbitals are used as inner orbitals.
- s (4s) and p (4p) orbitals are from the next higher energy level.

### Step 3: Conclusion on Assertion
Since the d-orbitals used for bonding are from the 3d subshell (inner d-orbitals), the assertion that `[Cr(H₂O)₆]³⁺` is an inner orbital complex is **true**.

### Step 4: Analyze the Reason
The reason states that water (H₂O) is a strong ligand generally.

- Water is classified as a weak field ligand according to the spectrochemical series. It does not cause significant pairing of electrons in the d-orbitals.
- In the case of `[Cr(H₂O)₆]³⁺`, the presence of three d-electrons does not lead to pairing due to the weak field nature of H₂O.

### Step 5: Conclusion on Reason
Since water is not a strong ligand, the reason provided is **false**.

### Final Conclusion
- The assertion is **true**: `[Cr(H₂O)₆]³⁺` is an inner orbital complex.
- The reason is **false**: H₂O is not a strong ligand generally.

Thus, the correct answer is that the assertion is true, but the reason is false.

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