Assertion: `FeSO_(4) and Fe_(2)(SO_(4))_(3)` undergoes intramolecular redox reaction on thermal decomposition
Reason: Both salts give brown solid of `Fe_(2)O_(3)` after decomposition.

Options

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

Answer

To solve the question regarding the assertion and reason about the thermal decomposition of FeSO4 and Fe2(SO4)3, let's break it down step by step.

### Step 1: Analyze the Assertion
The assertion states that "FeSO4 and Fe2(SO4)3 undergoes intramolecular redox reaction on thermal decomposition."

- **Analysis**:
- When FeSO4 is thermally decomposed, it does not undergo an intramolecular redox reaction. Instead, it undergoes an intermolecular redox reaction.
- The thermal decomposition of FeSO4 can be represented as:
\[ 2 \text{FeSO}_4 \rightarrow \text{Fe}_2\text{O}_3 + \text{SO}_2 + \text{SO}_3 \]
- This indicates that FeSO4 decomposes to form Fe2O3, SO2, and SO3, which involves the transfer of electrons between different molecules, hence it is an intermolecular redox reaction.

### Step 2: Analyze the Reason
The reason states that "Both salts give brown solid of Fe2O3 after decomposition."

- **Analysis**:
- This statement is correct. Both FeSO4 and Fe2(SO4)3, upon thermal decomposition, yield Fe2O3 as a product.
- The decomposition of Fe2(SO4)3 can be represented as:
\[ 2 \text{Fe}_2(\text{SO}_4)_3 \rightarrow \text{Fe}_2\text{O}_3 + 3 \text{SO}_3 \]
- This reaction also results in the formation of Fe2O3, which is a brown solid.

### Step 3: Conclusion
- Since the assertion is incorrect (it describes the reaction as intramolecular when it is actually intermolecular for FeSO4) and the reason is correct (both salts do yield Fe2O3), we conclude that:
- **Assertion**: False
- **Reason**: True

### Final Answer
The correct answer is that the assertion is false, but the reason is true.