PCC is an oxidizing agent. It converts alcohols to carbonyls, but is not strong enough to convert a primary alcohol into a carboxylic acid. It only converts primary alcohols to aldehydes, and secondary alcohols to ketones. 1-pentanol is a primary alcohol so it will be converted to the aldehyde pentanal.

PCC is an oxidizing agent that reacts with primary and secondary alcohols. However, it is less reactive than potassium permanganate and chromic acid. PCC differs from chromic acid by oxidizing primary alcohols to aldehydes, whereas chromic acid oxidizes primary alcohols and aldehydes to carboxylic acids. The desired product of the reaction given requires that the primary alcohol be oxidized to an aldehyde, so PCC is the best option.  is a reducing agent and would have the opposite effect than what is desired, yielding an alkane.

This is a two step reaction. In the first step, an alcohol is substituted for the bromine via an  reaction. Next, the alcohol is oxidized into a ketone with , a strong oxidizing agent used almost exclusively for converting alcohols into carbonyls.

 has the capability of oxidizing primary alcohols into aldehydes and secondary alcohols into ketones. However, it cannot oxidize aldehydes into carboxylic acids. To do that, we would need a stronger oxidizing agent such as .

First step: PCC oxidizes the primary alcohol to acetaldehyde

Second step: Grignard reagent attacks carbonyl carbon

Third step: Neutralization of the anion forms isoproyl alcohol

 is the only compound listed that is not a reducing agent. Pyridinium chlorochromate is a weak oxidizing agent and is often used to oxidize alcohols into carbony compounds. All of the other compounds are similar in that they function as reducing agents.

The reaction given would give an aldehyde. This type of reaction is called an oxidation reaction. Oxidation of a primary alcohol as in the reaction given by PCC (pyridinium chlorochromate) in  (dichloromethane) solvent yields an aldehyde. Like chromic acid, PCC oxidizes alcohols. However, PCC only oxidizes primary alcohols one step up to aldehydes and secondary alcohols to ketones. Chromic acid is a harsher oxidant because it will oxidize aldehydes to carboxylic acids. Below is the mechanism for this reaction:

The reaction given would give an aldehyde. This type of reaction is called an oxidation reaction. Oxidation of a primary alcohol as in the reaction given by PCC (pyridinium chlorochromate) in  (dichloromethane) solvent yields an aldehyde. Like chromic acid, PCC oxidizes alcohols. However, PCC only oxidizes primary alcohols one step up to aldehydes and secondary alcohols to ketones. Chromic acid is a harsher oxidant because it will oxidize aldehydes to carboxylic acids. Below is the mechanism for this reaction: Below is the mechanism:

PCC can be used to oxidize primary alcohols into aldehydes, or secondary alcohols into ketones. The starting material shown is a secondary alcohol, so the product will be a ketone (a carbonyl () group where the carbonyl carbon is also attached to two other carbons).

The following reaction schemes show the oxidation of all substrates, indicating that substrate II is in the highest oxidation state possible, and that an oxidation of this compound will not proceed.

Remember that in sulfuric acid and water, Na₂Cr₂O₇ will be converted to CrO_3, the active oxidant species. Furthermore, the oxidation mechanism involving this species includes the key step in which a hydrogen bonded to the carbon in question is eliminated, and simutaneously, a double bond from that carbon to an oxygen is installed. Thus, all substrates that feature at least one hydrogen bonded to the carbon to be oxidized can and will be oxidized in the precense of chromium trioxide.

Lastly, remember that these reactions are taking place in the prescence of water. While substrates such as compound III do not appear to be oxidizable, attack of water at the aldehyde carbon will give a dialcohol tetrathedral intermediate that can be immediately oxidized by chromium trioxide to the corresponding carboxylic acid. A similar mechanism occurs for substrate I, wherein, after the ketone oxidation state is achieved, an attack of water furnishes the same dialcohol intermediate that is oxidized to the carboxylic acid. Remember that the highest oxidation state available for organic compounds containing more than one carbon is the carboxylic acid oxidation state. Chromium trioxide will oxidize all organics to this oxidation state, unless directly-bonded hydrogens are not present in lower oxidation states, such as shown with substrate IV.