Which of the following is the most suitable requirement for the dehydration of ethanol to form an ether?

Sulphuric acid at 413K

The correct answer is option 1. Sulphuric acid at 413K.

The most suitable requirement for the dehydration of ethanol to form an ether is sulphuric acid at 413K.

Dehydration of ethanol to an ether (diethyl ether in this case) can occur using sulphuric acid as a catalyst. However, the temperature plays a crucial role in determining the product. At a higher temperature (443K), sulphuric acid promotes the elimination of a water molecule from ethanol, leading to the formation of ethene (an alkene) instead of an ether. This is because the reaction becomes kinetically favorable for the \(E_2\) elimination pathway at higher temperatures. At a lower temperature (413K), sulphuric acid can still act as a catalyst for dehydration, but the reaction follows an \(S_N2\) mechanism where an ethanol molecule acts as a nucleophile attacking the acidic proton of another ethanol molecule. This leads to the formation of the ether (diethyl ether). Sodium hydroxide \((NaOH)\) is a strong base and is not suitable for this dehydration reaction. Bases generally promote substitution reactions, not elimination reactions.

Therefore, using sulphuric acid at a controlled temperature of 413K is the most suitable requirement for the dehydration of ethanol to form diethyl ether.