Question

Name the reagent used in oxidation of a primary alcohol to aldehyde.

Answer 1

The primary alcohol is converted to aldehyde by the oxidation reaction using oxidizing agent. The oxidizing agent used also converts secondary alcohol to ketone. The main element of the oxidizing agent used is chromium.

Complete step by step answer:
The oxidation reaction is defined as the loss of electrons where the reactant loses its electrons to form a new product.
For oxidation of any compound, oxidizing agent is used. The main property of oxidizing agents is that it oxidizes the other substance in the reaction but itself gets reduced during the reaction.
The oxidation reaction of primary alcohol to aldehyde is a type of elimination reaction as the saturated compound having carbon-oxygen single bond is converted to unsaturated compound with carbon-oxygen double bond.
The primary alcohol is oxidized to aldehyde with the help of an oxidizing agent known as pyridinium chlorochromate (PCC). The pyridinium chlorochromate is used to oxidize primary alcohol to aldehyde and secondary alcohol to ketone. The other reagent used to convert primary alcohol to aldehyde is chromium trioxide and pyridine together known as Collins reagent.
During the oxidation of primary alcohol to aldehyde, the alcohol forms a coordinate bond with chromium (IV) atom which will result in the displacement of chlorine atom. Chlorine then acts as a base which results in oxidation of alcohol and reduces Cr(VI) to Cr(IV).

Note:
During the reaction of primary alcohol with PCC, make sure about the amount of water present. If water is present it will add to aldehyde to form a hydrate which will require a second equivalent of PCC for further oxidation. In ketone it is not a problem as it does not contain hydrogen atoms directly attached to carbon.