Read the passage carefully and answer the questions :

Replacement of a hydrogen atom in a hydrocarbon by an alkoxy or carboxyl group yields a class of compounds known as ethers. Ethers are classified as symmetrical or unsymmetrical on the basis of groups attached to the oxygen atoms. Diethyl ether, a symmetrical ether, has been widely used as an inhalation anesthetic. Ethers can be prepared by acid catalyzed intermolecular dehydration of alcohols and Williamson's synthesis. Acid catalyzed dehydration of alcohols is not generally preferred as it gives a mixture of elimination and substitution products.

In Williamson's synthesis, an alkyl halide is allowed to react with sodium alkoxide. Ethers containing substituted Alkyl groups may also be prepared by this method. The C-O bond in ether is weakly polar and is cleaved under drastic conditions with excess of hydrogen halides. In electrophilic substitution, the alkoxy group deactivates the aromatic ring and directs the incoming group to ortho and para positions.

Q) When ethanol is dehydrated in the presence of H2SO4 at 443 K and 413 K respectively the products formed are

The correct option is Ethene and ethoxyethane.

The dehydration of ethanol ($C_2{H}_{5}OH$) in the presence of concentrated sulfuric acid ($H_{2}S{O}_4$) is a temperature-dependent reaction. Depending on the temperature at which the reaction is carried out, it can yield either an alkene (via elimination) or an ether (via substitution).

1. At 443 K (High Temperature - Elimination):
When ethanol is heated with concentrated $H_{2}S{O}_4$ at 443 K, intramolecular dehydration takes place. A molecule of water is eliminated from a single ethanol molecule to form ethene, an alkene.
The chemical equation for this reaction is:
$$C{H}_{3}C{H}_{2}OH\underset{443\text{ K}}{\overset{H_{2}S{O}_4}{\to }}C{H}_2=C{H}_2+H_{2}O$$
Thus, the product at 443 K is ethene.

2. At 413 K (Lower Temperature - Substitution):
When ethanol is heated with concentrated $H_{2}S{O}_4$ at a lower temperature of 413 K, intermolecular dehydration occurs. Two molecules of ethanol condense together with the loss of one molecule of water to form ethoxyethane (diethyl ether), a symmetrical ether.
The chemical equation for this reaction is:

Thus, the product at 413 K is ethoxyethane.

Consequently, the dehydration products formed at 443 K and 413 K are ethene and ethoxyethane respectively.