Questions: Which of the following intermediates is thought to occur in the mechanism by which alkenes are hydrated in the presence of acid? carbanion carbocation free radical alkyne carbene

Solution Steps

In the acid-catalyzed hydration of alkenes, the reaction typically involves the addition of water across the double bond of the alkene. This process is catalyzed by an acid, which helps in the formation of an intermediate that facilitates the reaction.

The mechanism generally proceeds through the following steps:

1. Protonation of the alkene to form a carbocation intermediate.
2. Nucleophilic attack by water on the carbocation.
3. Deprotonation to yield the alcohol product.

The key intermediate in this mechanism is the carbocation, which is formed after the protonation of the alkene.

Given the options:

• Carbanion: This is a negatively charged carbon species, not typically involved in this mechanism.
• Carbocation: This is a positively charged carbon species and is the correct intermediate in the acid-catalyzed hydration of alkenes.
• Free radical: This involves unpaired electrons, not relevant here.
• Alkyne: This is a type of hydrocarbon, not an intermediate.
• Carbene: This is a neutral species with a divalent carbon, not involved in this mechanism.

Final Answer