Final answer:
To add an ethyl group to an oxygen atom and form an ether, you would need a strong acid such as sulfuric acid. The reaction proceeds through nucleophilic substitution.
Step-by-step explanation:
To add an ethyl group to an oxygen atom and form an ether, you would need a strong acid to protonate the oxygen, converting it into a good leaving group. The reagent commonly used for this purpose is sulfuric acid (H2SO4).
In the presence of sulfuric acid, the reaction proceeds as follows:
R-O-R' + H2SO4 → R-OH + R'-OH+
The alcohol formed (R-OH) can then be converted into the ether by reacting it with an alkyl halide (R'-X) in the presence of a base such as sodium hydroxide (NaOH) or potassium hydroxide (KOH). The reaction is known as nucleophilic substitution and results in the formation of the ether (R-O-R').