Question

The best reagent to convert \[pent - 3 - en - 2 - ol\] into \[pent - 3 - en - 2 - one\] is:
A.Pyridinium chlorochromate
B.Chromic anhydride in glacial acetic acid
C.Acidic dichromate
D.Acidic permanganate

Answer 1

Hint: The conversion of alcohol to ketones and aldehydes is considered as an important part of organic chemistry reactions. Basically the conversion of alcohol to aldehyde is known as partial oxidation because it can be further oxidized to form carboxylic acid.

Complete step by step answer:
As we all know, the conversion of \[pent - 3 - en - 2 - ol\] into \[pent - 3 - en - 2 - one\] is an oxidation reaction. The secondary alcohol is converted into ketone in this reaction.
Reaction:

In this reaction we can see that there is a double bond near the carbon to which the alcohol group is attached, so it should remain unaffected in this reaction.
To counter this problem we will use chromic anhydride in glacial acetic acid, this reagent will lock the double bond and oxidize the secondary alcohol to ketone and then again release the double bond as it was earlier.
So the best reagent used to convert \[pent - 3 - en - 2 - ol\] into \[pent - 3 - en - 2 - one\] is chromic anhydride in glacial acetic acid.
So, correct answer is option B.

Note: There are a number of oxidizing agents which are used for the oxidation of alcohols but the most common reagents are chromic acid (${H_2}C{r_2}{O_7}$) and pyridinium chlorochromate or we can say $PCC$.