The hydrolyzation of a nitrile with hydronium leads to a carboxylic acid. Only one choice is a carboxylic acid.

is the only strong oxidizing agent listed. It is strong enough to oxidize the primary alcohol even further to a carboxylic acid product. The rest of the compounds listed are weak oxidizing agents or reducing agents.

Aldehyde is not a derivative of carboxylic acid. Esters can be derived from carboxylic acids by reacting them with to form an acid chloride. From there, react it with an to form an ester. Amides can be derived from carboxylic acids by reacting them with to form an acid chloride. From there, react it with to form an amide.

As a general rule, any carboxylic acid derivative can be converted into al carboxylic acid when reacting with

After recognizing the reagents given, we know we need to begin with an alcohol. The alcohol choices differ only by how substituted they are.

For a carboxylic acid to form from a reaction with sodium dichromate and sulfuric acid, a primary alcohol needs to be available. Therefore, 1-pentanol is the correct answer.

The malonic ester is deprotonated at the most acidic hydrogen, the one on the carbon between the two oxygens. The electrons from that bond to the hydrogen form a carbon-carbon double bond while electrons from the oxygen-carbon double bond go to the oxygen atom. This is the enolate form. The chlorine leaves the 3-chloroheptane and the electrons from the carbon-carbon double bond bond to the carbon that the chlorine left. At the same time, the carbonyl is reformed. After deesterfication, 3-ethylheptanoic acid is formed.

PCC is considered a weak oxidizing agent. The reaction of a primary alcohol with PCC would only yield an aldehyde, while reaction with a secondary alcohol will yield a ketone. PCC will not be used to generate carboxylic acids.

A stronger oxidation, like or , is required to oxidize up to the carboxylic acid. Treatment of an ester with a base or treatment of carbon dioxide with a Grignard reagent are other ways of making carboxylic acids.