Question

Oxidation reactions involve loss of dihydrogen so they are also known as:

Answer 1

• Oxidation reactions involving the loss of dihydrogen from alcohol are known as Dehydrogenation reactions.
• It is one of the most important processes in the chemistry of petroleum because it converts starting alkanes which are inert into olefins and aromatic compounds.
• It is a highly endothermic reaction.
• This reaction generally consists of three steps:

Step 1: Formation of protonated alcohol

• In this particular step, the alcohol is reacted upon by a protic acid. Due to the single pair present on the oxygen atom, it acts as a Lewis base. This step is easily and quickly reversible.

Step 2: Carbocation formation

• In this step, the C–-O bond breaks which generate a carbocation. This is the slowest step in the mechanism of dehydration of alcohol. Therefore, the formation of the carbocation is said to be the rate-determining step.

Step 3: Alkene formation.

• This is the final step in the dehydration of alcohol. In this step, the proton generated is eliminated with the help of a base. The carbon atom neighbouring to the carbocation breaks the present C–-H bond to form C=C. Therefore, an alkene is formed.

Therefore, Oxidation reactions involving loss of dihydrogen are called Dehydrogenation reactions.