Ethanol on heating with conc. `H_2SO_4` at 443K

Options

A. Diethyl sulphate
B. Ethylene `C_2H_4`
C. Diethyl ether, `(C_2H_5)_2O`
D. ethyl hydrogen sulphate,`C_2H_5HSO_4`

Answer

To solve the problem of what happens when ethanol is heated with concentrated sulfuric acid (H₂SO₄) at 443 K, we can follow these steps:

### Step 1: Understand the Reactants
Ethanol (C₂H₅OH) is an alcohol, and when heated with concentrated sulfuric acid, it undergoes a dehydration reaction. Concentrated sulfuric acid acts as a dehydrating agent.

**Hint:** Identify the functional groups in the reactants and their roles in the reaction.

### Step 2: Protonation of Ethanol
When ethanol is mixed with concentrated sulfuric acid, the hydroxyl group (-OH) of ethanol gets protonated by the hydrogen ions (H⁺) from the sulfuric acid. This forms an oxonium ion (C₂H₅OH₂⁺).

**Hint:** Remember that protonation increases the electrophilicity of the alcohol, making it more reactive.

### Step 3: Formation of a Carbocation
The oxonium ion (C₂H₅OH₂⁺) is unstable and loses a water molecule (H₂O), leading to the formation of a carbocation (C₂H₅⁺). This step is critical as it generates a positively charged species that can undergo further reactions.

**Hint:** Consider the stability of the carbocation formed and how it influences the reaction pathway.

### Step 4: Elimination of a Proton
The carbocation can then undergo elimination, where a hydrogen ion (H⁺) is removed from a neighboring carbon atom. This results in the formation of an alkene. In this case, the product is ethylene (C₂H₄).

**Hint:** Look for the mechanism of elimination reactions, such as E1 or E2, and how they lead to the formation of alkenes.

### Step 5: Final Product
The final product of this reaction is ethylene (C₂H₄), which is an alkene. The overall reaction can be summarized as follows:

\[ \text{C}_2\text{H}_5\text{OH} \xrightarrow{\text{conc. } H_2SO_4, 443K} \text{C}_2\text{H}_4 + \text{H}_2\text{O} \]

**Hint:** Always write the balanced equation to summarize the reactants and products clearly.

### Conclusion
When ethanol is heated with concentrated sulfuric acid at 443 K, the product formed is ethylene (C₂H₄) along with the elimination of water.