Ethanol when passed over `Al_2O_3` at 623 K gives ________________.

Options

A. diethyl ether
B. ethane
C. butane
D. ethylene

Answer

To solve the question, "Ethanol when passed over `Al_2O_3` at 623 K gives ________________," we can follow these steps:

### Step 1: Understand the Reactants
Ethanol (C₂H₅OH) is an alcohol with a hydroxyl (-OH) functional group. It consists of two carbon atoms, five hydrogen atoms, and one hydroxyl group.

### Step 2: Identify the Catalyst
Al₂O₃ (aluminum oxide) is a dehydrating agent. This means it can remove water (H₂O) from the reactants during the reaction.

### Step 3: Analyze the Reaction Conditions
The reaction is conducted at a temperature of 623 K. This elevated temperature can facilitate the dehydration process, promoting the formation of alkenes.

### Step 4: Understand the Dehydration Process
When ethanol is passed over Al₂O₃, the hydroxyl group (-OH) from the ethanol can be removed along with a hydrogen atom from an adjacent carbon atom. This results in the formation of a double bond between the two carbon atoms.

### Step 5: Write the Reaction
The dehydration of ethanol can be represented as follows:

\[ \text{C}_2\text{H}_5\text{OH} \xrightarrow{\text{Al}_2\text{O}_3, 623 K} \text{C}_2\text{H}_4 + \text{H}_2\text{O} \]

Where:
- C₂H₄ is ethylene (an alkene).
- H₂O is the water that is removed.

### Step 6: Conclusion
Thus, when ethanol is passed over Al₂O₃ at 623 K, the product formed is ethylene (C₂H₄).

### Final Answer
Ethanol when passed over `Al_2O_3` at 623 K gives **ethylene**.

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