A : The dehydration of ethyl alcohol in presence of `Al_(2)O_(2)` at 633 K gives ethene.
R : The reaction proceed through the formation of carbocation intermediate.

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 determine whether the assertion (A) and the reason (R) are correct and if R is the correct explanation of A, we can analyze the dehydration of ethyl alcohol (ethanol) in the presence of aluminum oxide (Al2O3) at a temperature of 633 K.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that the dehydration of ethyl alcohol (C2H5OH) in the presence of Al2O3 at 633 K produces ethene (C2H4).
- Dehydration of alcohols typically involves the removal of a water molecule (H2O) from the alcohol.

2. **Reaction Mechanism**:
- When ethyl alcohol is heated with Al2O3, the alcohol undergoes dehydration.
- The hydroxyl group (OH) is removed, leading to the formation of a carbocation intermediate (C2H5+).

3. **Formation of Carbocation**:
- The reaction can be represented as follows:
\[ \text{C2H5OH} \xrightarrow{\text{Al2O3, 633 K}} \text{C2H5}^+ + \text{H2O} \]
- The carbocation (C2H5+) is formed when the OH group leaves.

4. **Elimination to Form Ethene**:
- The carbocation can then lose a hydrogen atom (H+) to form a double bond, resulting in the formation of ethene (C2H4):
\[ \text{C2H5}^+ \rightarrow \text{C2H4} + \text{H}^+ \]

5. **Conclusion on Assertion (A)**:
- The assertion is true because the dehydration of ethyl alcohol at 633 K does indeed produce ethene.

6. **Understanding the Reason (R)**:
- The reason states that the reaction proceeds through the formation of a carbocation intermediate.
- This is also true, as the formation of a carbocation is a key step in the dehydration process.

7. **Conclusion on Reason (R)**:
- The reason is correct because the formation of the carbocation is essential for the dehydration of ethyl alcohol to occur.

8. **Final Evaluation**:
- Since both the assertion (A) and the reason (R) are true, and R correctly explains A, we conclude that both statements are correct and R is the correct explanation of A.

### Final Answer:
Both A and R are true, and R is the correct explanation of A.