Give complete reaction when 2-molecules of Ethanol and 1-molecule of conc. H2SO4 are heated at 413K? ?

When you heat two molecules of ethanol (C2H5OH) with one molecule of concentrated sulfuric acid (H2SO4) at a temperature of 413 K, a dehydration reaction occurs. This process leads to the formation of ethene (C2H4) and water (H2O). Let's break down the reaction step by step to understand how this transformation takes place.

The Reaction Process

The overall reaction can be represented as follows:

• 2 C2H5OH + H2SO4 → 2 C2H4 + 2 H2O + H2SO4

In this reaction, sulfuric acid acts as a catalyst and is not consumed in the overall process. It facilitates the dehydration of ethanol, which involves the removal of a water molecule from the ethanol molecules.

Step-by-Step Breakdown

1. **Protonation of Ethanol**: The sulfuric acid donates a proton (H+) to the hydroxyl group (-OH) of ethanol. This step increases the electrophilicity of the ethanol, making it more reactive.

2. **Formation of Ethyl Hydrogen Sulfate**: The protonated ethanol can then react with another molecule of ethanol or with the sulfuric acid itself to form ethyl hydrogen sulfate (C2H5OSO3H). This intermediate is crucial for the next step.

3. **Dehydration**: The ethyl hydrogen sulfate can lose a water molecule (H2O) when heated, resulting in the formation of ethene. This step is where the actual dehydration occurs, leading to the release of water and the formation of the double bond in ethene.

Example of the Reaction

To visualize this, consider the following:

• When you heat ethanol, the heat energy helps break the bonds in the ethanol molecules.
• The sulfuric acid, acting as a catalyst, helps facilitate the removal of water.
• The result is the formation of ethene, which is a gaseous product at this temperature.

Key Points to Remember

In summary, the reaction between ethanol and concentrated sulfuric acid at elevated temperatures leads to the formation of ethene and water through a dehydration mechanism. The sulfuric acid plays a vital role as a catalyst, enhancing the reaction without being consumed. This process is an excellent example of how alcohols can be converted into alkenes through dehydration, a fundamental reaction in organic chemistry.