Assertion (A) `[Cr(H_(2)O_(6))]Cl_(2)` and `[Fe(H_(2)O)_(6)]Cl_(2)` are reducing in nature.
Reason (R) Unpaired electrons are present in their d-orbitals.

Options

A. Assertion and reason both are true, reason is correct explanation of assertion.
B. Assertion and reason both are true but reason is not the correct explanation of assertion.
C. Assertion is true, reason is false.
D. Assertion is false, reason is true.

Explanation

To solve the question regarding the assertion and reason concerning the complexes \([Cr(H_2O)_6]Cl_2\) and \([Fe(H_2O)_6]Cl_2\), we will analyze both parts step by step.

### Step 1: Analyze the Assertion
The assertion states that \([Cr(H_2O)_6]Cl_2\) and \([Fe(H_2O)_6]Cl_2\) are reducing in nature.

- **Understanding Reducing Nature**: A reducing agent is a substance that can donate electrons to another substance, thereby reducing it. Compounds that have unpaired electrons in their d-orbitals are generally more likely to act as reducing agents because they can lose electrons more easily.

### Step 2: Analyze the Reason
The reason states that unpaired electrons are present in their d-orbitals.

- **Chromium Complex**: In \([Cr(H_2O)_6]Cl_2\), chromium typically has an oxidation state of +2. The electron configuration of Cr in its elemental state is \([Ar] 3d^5 4s^1\). In the +2 oxidation state, it loses two electrons, resulting in a configuration of \(3d^4\). This means there are 4 unpaired electrons.

- **Iron Complex**: In \([Fe(H_2O)_6]Cl_2\), iron typically has an oxidation state of +2 as well. The electron configuration of Fe in its elemental state is \([Ar] 3d^6 4s^2\). In the +2 oxidation state, it loses two electrons, resulting in a configuration of \(3d^6\). In this case, there are also unpaired electrons, as not all electrons are paired in the d-orbitals.

### Step 3: Conclusion on Assertion and Reason
- Both the assertion and the reason are true. The presence of unpaired electrons in the d-orbitals of both complexes supports their reducing nature. However, the reason does not fully explain why these complexes are reducing agents; it merely states a fact about their electronic configuration.

### Final Answer
The correct option is:
**Option 2**: Assertion and reason both are true, but the reason is not the correct explanation of the assertion.