Final answer:
Butyllithium reacts with ethanol to form butane and the ethoxide ion, as it is a strong base that abstracts a hydrogen atom from the hydroxyl group of ethanol.
Step-by-step explanation:
When butyllithium reacts with ethanol, there is a strong nucleophilic attack from the butyllithium on the proton of the ethanol, leading to the formation of butane and the ethoxide ion. Butyllithium (C4H9Li) is a strong base as well as a nucleophile, and when reacting with ethanol (C2H5OH), it abstracts a hydrogen atom from the hydroxyl group, producing butane (C4H10) and the ethoxide ion (C2H5O−), thus the correct reaction would be the formation of butane and ethoxide ion, which is option 3 in the list provided. It is essential to remember that this reaction is essentially an acid-base reaction where the acidic proton on ethanol is abstracted by the basic butyllithium.