Question

Which of the following cannot form $C{H_3}COOH$ from ${C_2}{H_5}OH$?
A.$PCC$
B.$PDC$
C.${K_2}C{r_2}{O_7}/{H^ + }$
D.$KMn{O_4}/{H^ + }$

Answer 1

The process of conversion of ethyl alcohol to acetic acid is an oxidation reaction in which hydrogen atoms are replaced by oxygen atoms. Ethanol can be converted to acetic acid by using strong oxidising agents.

Complete step by step answer:
$PCC$ is Palladium ChloroChromate is a yellow orange salt that is used for the conversion of alcohols to carbonyl compounds and is highly effective for the conversion of mainly primary and secondary alcohols into aldehydes.
$PDC$ is Pyridinium Dichromate is also an orange colored salt. It is less acidic than $PCC$ and is more suitable for the oxidation of acid sensitive compounds.
${K_2}C{r_2}{O_7}/{H^ + }$, potassium dichromate is a strong reducing agent that oxidizes ethyl alcohol to acetic acid under strong acidic conditions.
$KMn{O_4}/{H^ + }$, potassium permanganate is also a very strong oxidizing agent, even stronger than potassium dichromate and this can also convert ethyl alcohol to acetic acid with ease.
Hence, both potassium dichromate and potassium permanganate under acidic conditions can be used for the process. So they can form acetic acid from ethyl alcohol but $PCC$ and $PDC$ cannot form.

So, the correct answer is A and B.

Note:
Pyridinium Dichromate in dichloromethane or dimethyl formamide is together called the “ Corey-Schmidt reagent” and it is used for the selective oxidation of allylic alcohols in presence of other alcoholic groups. The oxidation product depends on the solvent used. In dichloromethane, it conveniently oxidises primary alcohols to aldehydes at room temperature. Whereas in DMF, a polar solvent, non-conjugated primary alcohols are converted to carboxylic acids. However, conjugated alcohols like allyl primary alcohol give aldehyde only.